hdu 3549 Flow Problem (Dinic)
HDU Problem Flow
2023-09-11 14:21:10 时间
Flow Problem
Time Limit: 5000/5000 MS (Java/Others) Memory Limit: 65535/32768 K (Java/Others)
Total Submission(s): 21438 Accepted Submission(s): 10081
Time Limit: 5000/5000 MS (Java/Others) Memory Limit: 65535/32768 K (Java/Others)
Total Submission(s): 21438 Accepted Submission(s): 10081
Problem Description
Network flow is a well-known difficult problem for ACMers. Given a graph, your task is to find out the maximum flow for the weighted directed graph.
Input
The first line of input contains an integer T, denoting the number of test cases.
For each test case, the first line contains two integers N and M, denoting the number of vertexes and edges in the graph. (2 <= N <= 15, 0 <= M <= 1000)
Next M lines, each line contains three integers X, Y and C, there is an edge from X to Y and the capacity of it is C. (1 <= X, Y <= N, 1 <= C <= 1000)
The first line of input contains an integer T, denoting the number of test cases.
For each test case, the first line contains two integers N and M, denoting the number of vertexes and edges in the graph. (2 <= N <= 15, 0 <= M <= 1000)
Next M lines, each line contains three integers X, Y and C, there is an edge from X to Y and the capacity of it is C. (1 <= X, Y <= N, 1 <= C <= 1000)
Output
For each test cases, you should output the maximum flow from source 1 to sink N.
For each test cases, you should output the maximum flow from source 1 to sink N.
Sample Input
2
3 2
1 2 1
2 3 1
3 3
1 2 1
2 3 1
1 3 1
2
3 2
1 2 1
2 3 1
3 3
1 2 1
2 3 1
1 3 1
Sample Output
Case 1: 1
Case 2: 2
Case 1: 1
Case 2: 2
C/C++:
1 #include <map> 2 #include <queue> 3 #include <cmath> 4 #include <vector> 5 #include <string> 6 #include <cstdio> 7 #include <cstring> 8 #include <climits> 9 #include <iostream> 10 #include <algorithm> 11 #define INF 0x3f3f3f3f 12 using namespace std; 13 const int my_max = 20; 14 15 int N, M, my_map[my_max][my_max], my_source, my_sink 16 , my_dis[my_max]; 17 18 int my_dfs(int my_step, int my_ans) 19 { 20 if (my_step == my_sink) return my_ans; 21 22 int my_temp = my_ans; 23 for (int i = 1; i <= N && my_ans; ++ i) 24 { 25 if (my_dis[my_step] == my_dis[i] + 1 && my_map[my_step][i]) 26 { 27 int t = my_dfs(i, min(my_ans, my_map[my_step][i])); 28 my_map[my_step][i] -= t; 29 my_map[i][my_step] += t; 30 my_ans -= t; 31 } 32 } 33 return my_temp - my_ans; 34 } 35 36 bool my_bfs() 37 { 38 memset(my_dis, -1, sizeof(my_dis)); 39 queue <int> Q; 40 my_dis[my_sink] = 0; 41 Q.push(my_sink); 42 while (!Q.empty()) 43 { 44 int now = Q.front(); 45 for (int i = 1; i <= N; ++ i) 46 { 47 if (my_map[i][now] > 0 && my_dis[i] == -1) 48 { 49 my_dis[i] = my_dis[now] + 1; 50 Q.push(i); 51 } 52 } 53 if (now == my_source) return true; 54 Q.pop(); 55 } 56 return false; 57 } 58 59 int my_dinic() 60 { 61 int my_ans = 0; 62 while (my_bfs()) 63 my_ans += my_dfs(my_source, INF); 64 65 return my_ans; 66 } 67 68 int main() 69 { 70 int t; 71 scanf("%d", &t); 72 for (int i = 1; i <= t; ++ i) 73 { 74 memset(my_map, 0, sizeof(my_map)); 75 scanf("%d%d", &N, &M); 76 my_source = 1, my_sink = N; 77 78 while (M --) 79 { 80 int x, y, x_y; 81 scanf("%d%d%d", &x, &y, &x_y); 82 my_map[x][y] += x_y; 83 } 84 printf("Case %d: %d\n", i, my_dinic()); 85 } 86 return 0; 87 }
相关文章
- hdu 3549 Flow Problem 最大流问题 (模板题)
- HDU 3943 K-th Nya Number(数位DP)
- HDU 2993 MAX Average Problem(斜率优化DP)
- 【35.39%】【hdu 3333】Turing Tree
- 【hdu 6208】The Dominator of Strings
- 【hdu 6181】Two Paths
- hdu 4287 Intelligent IME
- HDU 5296 Annoying problem
- (hdu 简单题 128道)平方和与立方和(求一个区间的立方和和平方和)
- HDU - 5008 Boring String Problem (后缀数组+二分法+RMQ)
- Saving HDU hdu
- hdu 5055 Bob and math problem