page | section | no | title | submit |
113 | 1.5.1 | 例題1 | 括號序列 | POJ1141 |
116 | 1.5.1 | 例題2 | 棋盤分割 | POJ1191 |
117 | 1.5.1 | 例題3 | 決斗 | Sicily1822 |
117 | 1.5.1 | 例題4 | “舞蹈家”懷特先生 | ACM-ICPC Live Archive |
119 | 1.5.1 | 例題5 | 積木游戲 | http://202.120.80.191/problem.php?problemid=1244 |
123 | 1.5.2 | 例題1 | 方塊消除 | http://poj.org/problem?id=1390 |
123 | 1.5.2 | 例題2 | 公路巡邏 | http://202.120.80.191/problem.php?problemid=1600 |
125 | 1.5.2 | 例題3 | 并行期望值 | POJ1074 |
131 | 1.5.2 | 例題6 | 不可分解的編碼 | http://acmicpc-live-archive.uva.es/nuevoportal/data/problem.php?p=2475 |
133 | 1.5.2 | 例題7 | 青蛙的煩惱 | http://codewaysky.sinaapp.com/problem.php?id=1014 |
135 | 1.5.2 | 例題9 | 最優排序二叉樹 | http://judge.noi.cn/problem?id=1059 |
138 | 1.5.2 | 例題10 | Bugs公司 | POJ1038 |
139 | 1.5.2 | 例題11 | 迷宮統計 | http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=70&page=show_problem&problem=1472 |
142 | 1.5.2 | 例題12 | 貪吃的九頭龍 | http://judge.noi.cn/problem?id=1043 |
151 | 1.5.3 | 問題2 | 最長上升子序列問題 | http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=17&page=show_problem&problem=1475 |
151 | 1.5.3 | 問題3 | 最優二分檢索樹 | http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=15&page=show_problem&problem=1245 |
152 | 1.5.3 | 問題4 | 任務調度問題 | POJ1180 |
121 | 1.5.1 | 1.5.8 | 藝術館的火災 | http://221.192.240.23:9088/showproblem?problem_id=1366 |
144 | 1.5.2 | 1.5.10 | 快樂的蜜月 | http://judge.noi.cn/problem?id=1052 |
145 | 1.5.2 | 1.5.12 | 佳佳的筷子 | http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=14&page=show_problem&problem=1212 |
146 | 1.5.2 | 1.5.13 | 偷懶的工人 | POJ1337 |
146 | 1.5.2 | 1.5.15 | 平板涂色 | POJ1691 |
147 | 1.5.2 | 1.5.16 | 道路重建 | POJ1947 |
147 | 1.5.2 | 1.5.17 | 圓和多邊形 | http://acm.zju.edu.cn/onlinejudge/showProblem.do?problemCode=1679 |
148 | 1.5.2 | 1.5.18 | Jimmy落地 | POJ1661 |
148 | 1.5.2 | 1.5.19 | 免費糖果 | http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=13&page=show_problem&problem=1059 |
157 | 1.5.3 | 1.5.22 | 回文詞 | POJ1159 |
157 | 1.5.3 | 1.5.24 | 郵局 | POJ1160 |
158 | 1.5.3 | 1.5.26 | 奶牛轉圈 | POJ1946 |
158 | 1.5.3 | 1.5.27 | 元件折疊 | http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=14&page=show_problem&problem=1180 |
現在開始訓練一下DP:
遞歸動機的DP:
pku 1141?Brackets Sequence
黑書上講的第一個題目,題意就給出一個括號序列,包含有"(" ")" "[" "]" 求最少添加的括號數是的最終的序列是合法的并輸出這個序列。
思路:
首先這里求解的話要使用遞歸的思路,這是動態規劃產生的第一種動機,于是我們可以寫出記憶化搜索。進行求解。
dp[l][r] = min(dp[l][r],dp[l + 1][r - 1])如果s[l]與s[r]匹配的話。
否則我們就將該序列分成兩段分別求解(這也是求解DP線性模型的一種遞歸分解思路)
dp[l][r] = min(dp[l][r],dp[l][k] + dp[k + 1][r])
這里關鍵是怎么講可行解輸出呢?開始我是通過比較dp[l][r] 與 dp[l + 1][r ?-1] dp[l][k] + dp[k + 1][r]來判斷的后來發現這樣不對的 如果dp[l + 1][r - 1] = dp[l][k] + dp[k + 1][r]的話就會出現錯誤,而我們這里dp[l][r]確實從dp[l][k] + dp[k + 1][r]來的。所以,我們要另開一個二維數組記錄每種最優狀態的來源點。然后再遞歸的輸出即可。


#include <iostream> #include <cstdio> #include <cmath> #include <vector> #include <cstring> #include <algorithm> #include <string> #include <set> #include <functional> #include <numeric> #include <sstream> #include <stack> #include <map> #include <queue>#define CL(arr, val) memset(arr, val, sizeof(arr))#define lc l,m,rt<<1 #define rc m + 1,r,rt<<1|1 #define pi acos(-1.0) #define ll __int64 #define L(x) (x) << 1 #define R(x) (x) << 1 | 1 #define MID(l, r) (l + r) >> 1 #define Min(x, y) (x) < (y) ? (x) : (y) #define Max(x, y) (x) < (y) ? (y) : (x) #define E(x) (1 << (x)) #define iabs(x) (x) < 0 ? -(x) : (x) #define OUT(x) printf("%I64d\n", x) #define lowbit(x) (x)&(-x) #define Read() freopen("din.txt", "r", stdin) #define Write() freopen("dout.txt", "w", stdout);#define M 137 #define N 115using namespace std;const int inf = 0x7f7f7f7f; const int mod = 1000000007;int dp[N][N]; char s[N]; int mk[N][N];bool cmp(char a,char b) {if ((a == '(' && b == ')') || (a == '[' && b == ']')) return true;return false; } int dfs_DP(int l,int r) {int k;if (l > r) return 0;if (l == r) return (dp[l][r] = 1);if (dp[l][r] != inf) return dp[l][r];if (cmp(s[l],s[r])){if (l + 1 == r){dp[l][r] = 0;mk[l][r] = -1;}else{dfs_DP(l + 1,r - 1);if (dp[l][r] > dp[l + 1][r - 1]){dp[l][r] = dp[l + 1][r - 1];mk[l][r] = -1;}// dp[l][r] = min(dp[l][r],dfs_DP(l + 1,r - 1)); // printf(">>>**%d %d %d %d\n",l,r,dp[l][r],dp[l + 1][r - 1]); }}for (k = l; k <= r - 1; ++k){dfs_DP(l,k); dfs_DP(k + 1,r);if (dp[l][r] > dp[l][k] + dp[k + 1][r]){dp[l][r] = dp[l][k] + dp[k + 1][r];mk[l][r] = k;} // dp[l][r] = min(dp[l][r],dfs_DP(l,k) + dfs_DP(k + 1,r)); }return dp[l][r]; }void print(int l,int r) {if (l > r) return;if (l == r){if (s[l] == '(' || s[l] == ')') printf("()");else if (s[l] == '[' || s[l] == ']') printf("[]");return;}if (cmp(s[l],s[r]) && mk[l][r] == -1){printf("%c",s[l]);print(l + 1,r - 1);printf("%c",s[r]);}else{print(l,mk[l][r]);print(mk[l][r] + 1,r);} } int main() { // Read(); // Write();int i,j;scanf("%s",s);int n = strlen(s);CL(mk,-1);for (i = 0; i <= n; ++i){for (j = 0; j <= n; ++j){dp[i][j] = inf;}}dfs_DP(0,n - 1); // printf("%d\n",dp[0][n - 1]);print(0,n - 1);printf("\n");return 0; }
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?pku 1191?棋盤分割
思路:
棋盤橫著切豎著切,然后遞歸將棋盤不斷縮小到能夠求解的狀態。記憶化搜索。這里中間計算值可能會超0x7f7f7f7f,所以最大值取大一點。這里讓哥條了很長時間。。


#include <iostream> #include <cstdio> #include <cmath> #include <vector> #include <cstring> #include <algorithm> #include <string> #include <set> #include <functional> #include <numeric> #include <sstream> #include <stack> #include <map> #include <queue>#define CL(arr, val) memset(arr, val, sizeof(arr))#define lc l,m,rt<<1 #define rc m + 1,r,rt<<1|1 #define pi acos(-1.0) #define ll __int64 #define L(x) (x) << 1 #define R(x) (x) << 1 | 1 #define MID(l, r) (l + r) >> 1 #define Min(x, y) (x) < (y) ? (x) : (y) #define Max(x, y) (x) < (y) ? (y) : (x) #define E(x) (1 << (x)) #define iabs(x) (x) < 0 ? -(x) : (x) #define OUT(x) printf("%I64d\n", x) #define lowbit(x) (x)&(-x) #define Read() freopen("din.txt", "r", stdin) #define Write() freopen("dout.txt", "w", stdout);#define M 137 #define N 10using namespace std;const int inf = 0x7f7f7f7f; const int mod = 1000000007;int mat[N][N]; int s[N][N][N][N]; int dp[N][N][N][N][20]; ll map[N][N];int n;int DP(int x1,int y1,int x2,int y2,int no) {int x,y;if (no == 1) return dp[x1][y1][x2][y2][no];if (dp[x1][y1][x2][y2][no] != -1) return dp[x1][y1][x2][y2][no];int ans = 999999999;for (x = x1; x < x2; ++x){ans = min(ans,min(DP(x1,y1,x,y2,no - 1) + s[x + 1][y1][x2][y2],DP(x + 1,y1,x2,y2,no - 1) + s[x1][y1][x][y2]));}for (y = y1; y < y2; ++y){ans = min(ans,min(DP(x1,y1,x2,y,no - 1) + s[x1][y + 1][x2][y2],DP(x1,y + 1,x2,y2,no - 1) + s[x1][y1][x2][y]));}return (dp[x1][y1][x2][y2][no] = ans); } int main() { // Read();int i,j;scanf("%d",&n);int sum = 0;for (i = 1; i <= 8; ++i){for (j = 1; j <= 8; ++j){scanf("%d",&mat[i][j]);sum += mat[i][j];}}CL(s,0); CL(dp,-1);int x1,y1,x2,y2;for (x1 = 1; x1 <= 8; ++x1){for (y1 = 1; y1 <= 8; ++y1){for (x2 = x1; x2 <= 8; ++x2){for (y2 = y1; y2 <= 8; ++y2){ // printf("%d %d %d %d\n",x1,y1,x2,y2);for (i = x1; i <= x2; ++i){for (j = y1; j <= y2; ++j){s[x1][y1][x2][y2] += mat[i][j];}}s[x1][y1][x2][y2] *= s[x1][y1][x2][y2];dp[x1][y1][x2][y2][1] = s[x1][y1][x2][y2];}}}}DP(1,1,8,8,n);double ans = (1.0*dp[1][1][8][8][n])/(1.0*n) - (1.0*sum*sum)/(1.0*n*n);printf("%.3f\n",sqrt(ans));return 0; }
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?sicily 1822?Fight Club
題意:黑書
思路:
開始吧題意理解錯了,一位如果判斷i必須從i開始一次與i + 1,i +2比較呢。SB了。。
dp[i][j]表示i能否與j相遇,記住這里是相遇不表示i與j誰能打敗誰。如果判斷x點,我們把x點查分為x與n + 1,這樣講原來的環轉化成連,然后求x與n +1是否能夠相遇即可
dp[i][j] = (dp[i][k] && dp[k][j] && (mat[i][k],mat[j][k])),mat[i][j]表示i能否打敗j


#include <iostream> #include <cstdio> #include <cmath> #include <vector> #include <cstring> #include <algorithm> #include <string> #include <set> #include <functional> #include <numeric> #include <sstream> #include <stack> #include <map> #include <queue>#define CL(arr, val) memset(arr, val, sizeof(arr))#define lc l,m,rt<<1 #define rc m + 1,r,rt<<1|1 #define pi acos(-1.0) #define ll __int64 #define L(x) (x) << 1 #define R(x) (x) << 1 | 1 #define MID(l, r) (l + r) >> 1 #define Min(x, y) (x) < (y) ? (x) : (y) #define Max(x, y) (x) < (y) ? (y) : (x) #define E(x) (1 << (x)) #define iabs(x) (x) < 0 ? -(x) : (x) #define OUT(x) printf("%I64d\n", x) #define lowbit(x) (x)&(-x) #define Read() freopen("din.txt", "r", stdin) #define Write() freopen("dout.txt", "w", stdout);#define M 137 #define N 50using namespace std;const int inf = 0x7f7f7f7f; const int mod = 1000000007;int mat[N][N];int dp[N][N]; int seq[N]; bool vt[N][N];int n; int DP(int l,int r) {int k;if (vt[l][r]) return dp[l][r];for (k = l + 1; k <= r - 1; ++k){dp[l][r] = (DP(l,k)&&DP(k,r)&&(mat[seq[l]][seq[k]] || mat[seq[r]][seq[k]]));if (dp[l][r]) break;}vt[l][r] = true;return dp[l][r]; } int main() { // Read();int T,i,j;scanf("%d",&T);while (T--){scanf("%d",&n);CL(mat,0);for (i = 1; i <= n; ++i)for (j = 1; j <= n; ++j)scanf("%d",&mat[i][j]);for (i = 1; i <= n; ++i){CL(dp,0); CL(vt,false);int pos = (i - 1);if (pos == 0) pos = n;int ln = 0;for (j = i; j <= n; ++j) seq[++ln] = j;for (j = 1; j <= i - 1; ++j) seq[++ln] = j;seq[++ln] = n + 1;for (j = 1; j <= n; ++j){dp[j][j + 1] = dp[j + 1][j] = 1;vt[j][j + 1] = vt[j + 1][j] = true;}DP(1,ln);if (dp[1][ln]) printf("1\n");else printf("0\n");} // if (T != 0)printf("\n");}return 0; }
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hdu 3632?A Captivating Match
題意:
這題和上題目意思一樣,只不過這里是序列1-n然后每個人可以選擇左右兩邊的人進行對決,我剛開始看到這題目的時候,就以為是上邊那道題目,結果樣例過了,就是不對。
思路:
這里某個人i如果能夠勝出,那么他一定能夠和0點并且和n + 1點相遇。(與上題一樣,抽象出來的兩個點)。然后我們只要枚舉任意兩點是否能夠相遇即可,
dp[i][j] = (dp[i][k] && dp[k][j] && (mat[i][k],mat[j][k])),mat[i][j]表示i能否打敗j, ? 這里根據i到j的距離進行遞推的。


#include <iostream> #include <cstdio> #include <cmath> #include <vector> #include <cstring> #include <algorithm> #include <string> #include <set> #include <functional> #include <numeric> #include <sstream> #include <stack> #include <map> #include <queue>#define CL(arr, val) memset(arr, val, sizeof(arr)) #define lc l,m,rt<<1 #define rc m + 1,r,rt<<1|1 #define pi acos(-1.0) #define ll __int64 #define L(x) (x) << 1 #define R(x) (x) << 1 | 1 #define MID(l, r) (l + r) >> 1 #define Min(x, y) (x) < (y) ? (x) : (y) #define Max(x, y) (x) < (y) ? (y) : (x) #define E(x) (1 << (x)) #define iabs(x) (x) < 0 ? -(x) : (x) #define OUT(x) printf("%I64d\n", x) #define lowbit(x) (x)&(-x) #define Read() freopen("din.txt", "r", stdin) #define Write() freopen("dout.txt", "w", stdout);#define M 30007 #define N 117using namespace std;const int inf = 100000007; const int mod = 1000000007;int val[N]; int mat[N][N]; int n; int dp[N][N]; bool vt[N][N];bool isok(int i,int j,int k) {if (dp[i][k] && dp[k][j] && (mat[i][k] || mat[j][k])) return true;else return false; } int main() { // Read();int T,i,j;int cas = 1;scanf("%d",&T);while (T--){scanf("%d",&n);for (i = 1; i <= n; ++i) scanf("%d",&val[i]);CL(mat,0);//記住要初始化for (i = 1; i <= n; ++i)for (j = 1; j <= n; ++j) scanf("%d",&mat[i][j]);CL(dp,0);for (i = 0; i <= n + 1; ++i) dp[i][i + 1] = dp[i + 1][i] = 1;int k,p;for (k = 2; k <= n; ++k)//遞推策略 {for (i = 0; i + k <= n + 1; ++i){j = i + k;for (p = i + 1; p <= j - 1; ++p){if (isok(i,j,p)){dp[i][j] = 1;}}}}int ans = 0;for (i = 1; i <= n; ++i){if (dp[0][i] && dp[i][n + 1] && val[i] > ans) ans = val[i]; //i能否殺到0并且能夠殺到n + 1 }printf("Case %d: %d\n",cas++,ans);}return 0; }
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pku 1390?Blocks
題意:看給書吧..
思路:
我們考慮的是最后一段是單獨消去還是和前邊的一起消去,這樣就可以構造出遞歸的遞推式了。
題目的方塊可以表示稱color[i],len[i],1<=i<=l
這里l表示有多少"段"不同的顏色方塊
color[i]表示第i段的顏色,len[i]表示第i段的方塊長度
讓f[i,j,k]表示把(color[i],len[i]),(color[i+1],len[i+1]),...,(color[j-1],len[j-1]),(color[j],len[j]+k)合并的最大得分
考慮(color[j],len[j]+k)這一段,要不馬上消掉,要不和前面的若干段一起消掉
1.如果馬上消掉,就是f[i,j-1,0]+(len[j]+k)^2
2.如果和前面的若干段一起消,可以假設這"若干段"中最后一段是p,則此時的得分是f[i,p,k+len[j]]+f[p+1,j-1,0]
于是f[i,j,k] = max{ f[i,j-1,0]+(len[j]+k)^2, f[i,p,k+len[j]]+f[p+1,j-1,0]?


#include <iostream> #include <cstdio> #include <cmath> #include <vector> #include <cstring> #include <algorithm> #include <string> #include <set> #include <functional> #include <numeric> #include <sstream> #include <stack> #include <map> #include <queue> #include <utility>#define CL(arr, val) memset(arr, val, sizeof(arr))#define lc l,m,rt<<1 #define rc m + 1,r,rt<<1|1 #define pi acos(-1.0) #define ll long long #define L(x) (x) << 1 #define R(x) (x) << 1 | 1 #define MID(l, r) (l + r) >> 1 #define Min(x, y) (x) < (y) ? (x) : (y) #define Max(x, y) (x) < (y) ? (y) : (x) #define E(x) (1 << (x)) #define iabs(x) (x) < 0 ? -(x) : (x) #define OUT(x) printf("%I64d\n", x) #define lowbit(x) (x)&(-x) #define Read() freopen("din.txt", "r", stdin) #define Write() freopen("dout.txt", "w", stdout);#define M 137 #define N 207using namespace std;const int inf = 0x7f7fffff; const ll mod = 1000000007;int dp[N][N][N]; int a[N],of[N],b[N]; int n,ln;int q_DP(int l,int r,int k) {int p;if (dp[l][r][k] != 0) return dp[l][r][k];if (l == r){return (dp[l][r][k] = (b[r] + k)*(b[r] + k));}int ans = 0;ans = max(ans,q_DP(l,r - 1,0) + (b[r] + k)*(b[r] + k));for (p = l; p + 1 <= r - 1; ++p){if (of[r] == of[p])ans = max(ans,q_DP(l,p,k + b[r]) + q_DP(p + 1,r - 1,0));}return dp[l][r][k] = ans; } int main() { // Read();int i;int T,cas = 1;scanf("%d",&T);while (T--){scanf("%d",&n);ln = 0; CL(a,0);for (i = 0; i < n; ++i){scanf("%d",&a[i]);}ln = 0; int ct = 0;for (i = 0; i < n; ++i){if (a[i] != a[i + 1]){b[++ln] = ct + 1;of[ln] = a[i];ct = 0;}else ct++;} // b[++ln] = ct; // of[ln] = a[n - 1];CL(dp,0);q_DP(1,ln,0);printf("Case %d: %d\n",cas++,dp[1][ln][0]);}return 0; }
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?
?多決策動機的DP:
https://icpcarchive.ecs.baylor.edu/index.php?option=com_onlinejudge&Itemid=8&page=show_problem&problem=32
題意:黑書。。
思路:
這里每一步要么走左腿,要么走右腿,要么原地不動。DFS求解肯定超時,因為狀態數太多,所以我們只好利用DP記錄所有狀態,然后通過每一步的決策。求解所有滿足條件的狀態。


#include <iostream> #include <cstdio> #include <cmath> #include <vector> #include <cstring> #include <algorithm> #include <string> #include <set> #include <functional> #include <numeric> #include <sstream> #include <stack> #include <map> #include <queue>#define CL(arr, val) memset(arr, val, sizeof(arr))#define lc l,m,rt<<1 #define rc m + 1,r,rt<<1|1 #define pi acos(-1.0) #define ll __int64 #define L(x) (x) << 1 #define R(x) (x) << 1 | 1 #define MID(l, r) (l + r) >> 1 #define Min(x, y) (x) < (y) ? (x) : (y) #define Max(x, y) (x) < (y) ? (y) : (x) #define E(x) (1 << (x)) #define iabs(x) (x) < 0 ? -(x) : (x) #define OUT(x) printf("%I64d\n", x) #define lowbit(x) (x)&(-x) #define Read() freopen("din.txt", "r", stdin) #define Write() freopen("dout.txt", "w", stdout);#define M 137 #define N 10017using namespace std;const int inf = 0x7f7fffff; const int mod = 1000000007;int a[N]; int dp[5][5][3];int getS(int x,int y) {if (x == 0) return 2;else if (x == y) return 1;else if (abs(x - y) == 2) return 4;else return 3; } int main() { // Read();int i,j,k;int n;a[0] = 0;while (~scanf("%d",&a[1])){if (a[1] == 0) break;i = 2;while (scanf("%d",&a[i])){if (a[i] == 0) break;i++;}n = i - 1;for (i = 0; i <= 4; ++i){for (j = 0; j <= 4; ++j){for (k = 0; k <= 1; ++k)dp[i][j][k] = inf;}}dp[0][0][0] = 0;int u = 0, v = 1;for (k = 0; k < n; ++k){for (i = 0; i <= 4; ++i){for (j = 0; j <= 4; ++j){if (dp[i][j][u] != inf){if (a[k + 1] != j) //保證左右腳不能在一起dp[a[k + 1]][j][v] = min(dp[a[k + 1]][j][v],dp[i][j][u] + getS(i,a[k + 1]));if (i != a[k + 1])dp[i][a[k + 1]][v] = min(dp[i][a[k + 1]][v],dp[i][j][u] + getS(j,a[k + 1]));}}}swap(u,v); //滾動數組優化for (i = 0; i <= 4; ++i){for (j = 0; j <= 4; ++j){dp[i][j][v] = inf;}}}int ans = inf;for (i = 0; i <= 4; ++i){if (i != a[n])ans = min(dp[i][a[n]][u],ans);}for (j = 0; j <= 4; ++j){if (j != a[n])ans = min(dp[a[n]][j][u],ans);}printf("%d\n",ans);}return 0; }
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積木游戲
題意:。。。
思路:
就是按著黑書上的第一種思路做的,這里有個地方卡了一下, 就是j表示的類成了j堆,在枚舉的時候不能只到m-1否則最后累到第m的堆的最后一個也就不存在了,。


#include <iostream> #include <cstdio> #include <cmath> #include <vector> #include <cstring> #include <algorithm> #include <string> #include <set> #include <functional> #include <numeric> #include <sstream> #include <stack> #include <map> #include <queue> #include <utility>#define CL(arr, val) memset(arr, val, sizeof(arr))#define lc l,m,rt<<1 #define rc m + 1,r,rt<<1|1 #define pi acos(-1.0) #define ll long long #define L(x) (x) << 1 #define R(x) (x) << 1 | 1 #define MID(l, r) (l + r) >> 1 #define Min(x, y) (x) < (y) ? (x) : (y) #define Max(x, y) (x) < (y) ? (y) : (x) #define E(x) (1 << (x)) #define iabs(x) (x) < 0 ? -(x) : (x) #define OUT(x) printf("%I64d\n", x) #define lowbit(x) (x)&(-x) #define Read() freopen("din.txt", "r", stdin) #define Write() freopen("dout.txt", "w", stdout);#define M 137 #define N 107using namespace std;const int inf = 0x7f7fffff; const ll mod = 1000000007;int dp[N][N][N][4]; bool vt[N][N][N][4]; int a[N][4][4]; int n,m;bool over(int i,int x,int j,int y) {int sda = max(a[i][x][0],a[i][x][1]);int sdb = min(a[i][x][0],a[i][x][1]);int pda = max(a[j][y][0],a[j][y][1]);int pdb = min(a[j][y][0],a[j][y][1]);if (sda <= pda && sdb <= pdb) return true;else return false; } int main() { // Read();int i,j,k,p,q;int x,y,z;scanf("%d%d",&n,&m);CL(a,0);for (i = 1; i <= n; ++i){scanf("%d%d%d",&x,&y,&z);//表示第i個面的的長寬高a[i][0][0] = x; a[i][0][1] = y; a[i][0][2] = z;a[i][1][0] = y; a[i][1][1] = z; a[i][1][2] = x;a[i][2][0] = z; a[i][2][1] = x; a[i][2][2] = y;}CL(dp,0); CL(vt,false);vt[0][0][0][0] = true;for (i = 0; i < n; ++i){for (j = 0; j <= min(i,m); ++j){for (k = 0; k <= i; ++k){for (p = 0; p < 3; ++p){if (vt[i][j][k][p]){for (q = 0; q < 3; ++q){//可以累加if (over(i + 1,q,k,p)){dp[i + 1][j][i + 1][q] = max(dp[i + 1][j][i + 1][q],dp[i][j][k][p] + a[i + 1][q][2]);vt[i + 1][j][i + 1][q] = true;}//另起一堆dp[i + 1][j + 1][i + 1][q] = max(dp[i + 1][j + 1][i + 1][q],dp[i][j][k][p] + a[i + 1][q][2]);vt[i + 1][j + 1][i + 1][q] = true;//直接跳過dp[i + 1][j][k][p] = max(dp[i + 1][j][k][p],dp[i][j][k][p]);vt[i + 1][j][k][p] = true; // printf(">>>>%d %d %d\n",dp[i + 1][j][i + 1][q],dp[i + 1][j + 1][i + 1][q],dp[i + 1][j][k][p]); }}}}}}int ans = 0; // printf("%d %d\n",n,m);for (k = 1; k <= n; ++k){for (p = 0; p < 3; ++p){ // printf(">>>>>>%d\n",dp[n][m][k][p]);ans = max(ans,dp[n][m][k][p]);}}printf("%d\n",ans);return 0; }
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?公路巡邏
思路:
dp[i][j]表示到達在時間為j時第i個關口與巡邏車相遇的最少次數 dp[i + 1][j + 1] = max(dp[i + 1][j + 1],dp[i][j] + s); s表示目標車在 [j, j + k]時間段內從第i個關口出發到i + 1個關口與巡邏車相遇的次數。
其實狀態轉移很好想,只是在車輛相遇上腦子短路了,我們只要排除不相遇的就好了。
這里還沒有優化。。


#include <iostream> #include <cstdio> #include <cmath> #include <vector> #include <cstring> #include <algorithm> #include <string> #include <set> #include <functional> #include <numeric> #include <sstream> #include <stack> #include <map> #include <queue>#define CL(arr, val) memset(arr, val, sizeof(arr))#define lc l,m,rt<<1 #define rc m + 1,r,rt<<1|1 #define pi acos(-1.0) #define ll long long #define L(x) (x) << 1 #define R(x) (x) << 1 | 1 #define MID(l, r) (l + r) >> 1 #define Min(x, y) (x) < (y) ? (x) : (y) #define Max(x, y) (x) < (y) ? (y) : (x) #define E(x) (1 << (x)) #define iabs(x) (x) < 0 ? -(x) : (x) #define OUT(x) printf("%I64d\n", x) #define lowbit(x) (x)&(-x) #define Read() freopen("din", "r", stdin) #define Write() freopen("dout", "w", stdout);#define M 86405 #define N 55using namespace std;const int inf = 0x7f7f7f7f; const int mod = 1000000007;struct node {int s,e; }nd[N][N]; int ln[N];int dp[N][M]; bool vt[N][M]; int n,m;int main() { // Read();int i,j,k;int ni,di;char ti[7];scanf("%d%d",&n,&m);CL(ln,0);CL(nd,0);for (j = 0; j < m; ++j){scanf("%d%s%d",&ni,ti,&di);int no = 0; int sum = 0;for (i = 0; i < 6; ++i){if (i%2 == 1){no = no*10 + ti[i] - '0';int tmp = 0;if (i == 1) tmp = 3600;else if (i == 3) tmp = 60;else tmp = 1;sum += no*tmp;no = 0;}else{no = no*10 + ti[i] - '0';}}int &p = ln[ni];nd[ni][p].s = sum;nd[ni][p].e = sum + di;p++;}for (i = 1; i <= n; ++i){for (j = 0; j <= 86400; ++j){dp[i][j] = inf;}}CL(vt,false); dp[1][21600] = 0;vt[1][21600] = true;for (i = 1; i < n; ++i){for (j = 21600; j <= 51000; ++j){if (vt[i][j]){for (k = 300; k <= 600; ++k){int s = 0;int p;for (p = 0; p < ln[i]; ++p){if (nd[i][p].e == j + k) s++;else{if (j <= nd[i][p].s && j + k <= nd[i][p].e) continue;if (j >= nd[i][p].s && j + k >= nd[i][p].e) continue;s++;}}dp[i + 1][j + k] = min(dp[i + 1][j + k],dp[i][j] + s);vt[i + 1][j + k] = true;}}}}int ans = inf;int tim = 0;for (i = 21600; i <= 51000; ++i){if (vt[n][i] && dp[n][i] < ans){ans = dp[n][i];tim = i;}}int hh = tim/3600;tim -= hh*3600;int mm = tim/60;tim -= mm*60;int ss = tim;printf("%d\n%02d%02d%02d\n",ans,hh,mm,ss);return 0; }
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?===================================================================
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poj 1337?A Lazy Worker
題意:
一個懶工人,他想工作的時間盡量少。有N個任務,每個任務有開始時間和deadline,工人完成這個工作需要ti時間。如果某個時刻有工作可以做(這里是說,如果從這個時刻開始某個工作,在deadline之前能夠完成),那么這個工人必須做,但是如果這個時刻存在著多余1件工作可以做,工人可以選擇;假設這個時刻沒有工作可以做了,工人就可以偷懶直到有新的任務到來
思路:
剛開始以為只要我一空下來有工作,我就必須從這一點開始工作來著,其實不是的,只要在最晚期限之前完成該工作即可。
dp[i]表示在時間點i時,完成工作所需要的最少時間,dp[i + 1] = min(dp[i + 1],dp[i])當該時間沒有工作干時,當有多個工作時,dp[i + tk] = min(dp[i + tk],dp[i] + tk) k表示第k個工作可以再時間點i完成
這里注意inf = 0x3fffffff 因為會有inf的相加,這里快整死我了,給很長時間沒有條出來。。


#include <iostream> #include <cstdio> #include <cmath> #include <vector> #include <cstring> #include <algorithm> #include <string> #include <set> #include <functional> #include <numeric> #include <sstream> #include <stack> #include <map> #include <queue> #include <list>#define CL(arr, val) memset(arr, val, sizeof(arr))#define lc l,m,rt<<1 #define rc m + 1,r,rt<<1|1 #define pi acos(-1.0) #define ll long long #define L(x) (x) << 1 #define R(x) (x) << 1 | 1 #define MID(l, r) (l + r) >> 1 #define Min(x, y) (x) < (y) ? (x) : (y) #define Max(x, y) (x) < (y) ? (y) : (x) #define E(x) (1 << (x)) #define iabs(x) (x) < 0 ? -(x) : (x) #define OUT(x) printf("%I64d\n", x) #define lowbit(x) (x)&(-x) #define Read() freopen("din.txt", "r", stdin) #define Write() freopen("dout.txt", "w", stdout);#define M 107 #define N 117 using namespace std;const ll mod = 1000000007; const int inf = 0x3fffffff;struct node {int ti,ai,di; }nd[N];int dp[260]; vector<int> work[260];int main() { // Read(); // printf("%d \n%d\n",0x7fffffff,0x3fffffff);int T;int i,j;int n;scanf("%d",&T);while (T--){scanf("%d",&n);int s = inf, e = 0;for (i = 0; i < n; ++i){scanf("%d%d%d",&nd[i].ti,&nd[i].ai,&nd[i].di);s = min(s,nd[i].ai); e = max(e,nd[i].di);}for (i = s; i <= e; ++i){work[i].clear();for (j = 0; j < n; ++j){if (i >= nd[j].ai && i + nd[j].ti <= nd[j].di){work[i].push_back(j);}}}for (i = s; i <= e; ++i) dp[i] = inf;dp[s] = 0;for (i = s; i < e; ++i){if (work[i].size() == 0) dp[i + 1] = min(dp[i + 1],dp[i]);else{int sz = work[i].size();for (int j = 0; j < sz; ++j){int k = work[i][j];dp[i + nd[k].ti] = min(dp[i + nd[k].ti],dp[i] + nd[k].ti);}}}printf("%d\n",dp[e]);}return 0; }
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