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It is vitally important to have all the cities connected by highways in a war. If a city is occupied by the enemy, all the highways from/toward that city are closed. We must know immediately if we need to repair any other highways to keep the rest of the cities connected. Given the map of cities which have all the remaining highways marked, you are supposed to tell the number of highways need to be repaired, quickly.
For example, if we have 3 cities and 2 highways connecting city1-city2 and city1-city3. Then if city1 is occupied by the enemy, we must have 1 highway repaired, that is the highway city2-city3.
Input
Each input file contains one test case. Each case starts with a line containing 3 numbers N (<1000), M and K, which are the total number of cities, the number of remaining highways, and the number of cities to be checked, respectively. Then M lines follow, each describes a highway by 2 integers, which are the numbers of the cities the highway connects. The cities are numbered from 1 to N. Finally there is a line containing K numbers, which represent the cities we concern.
Output
For each of the K cities, output in a line the number of highways need to be repaired if that city is lost.
Sample Input
3 2 31 21 31 2 3
Sample Output
100
/* 求在一個連通圖中去掉一個節點後 需要至少添加幾條邊才能使剩下的節點連通 1. 用dfs求地區數 減1 即可。 去掉的那個節點將其visited[i]置為1 在dfs中通過該節點串連的節點就被分隔開來了。*/#include "iostream"#include "cstring"using namespace std;#define MAX 1001int map[MAX][MAX];int visited[MAX];int n, m, k;void dfs(int j) { visited[j] = 1; for (int i = 1; i <= n; i++) { if (!visited[i] && map[j][i] == 1) { dfs(i); } }}int main() { cin >> n >> m >> k; while (m--) { int a, b; cin >> a >> b; map[a][b] = map[b][a] = 1; } while (k--) { int num = 0; int l; cin >> l; memset(visited, 0, sizeof(visited)); visited[l] = 1; for(int i=1; i<=n; i++) if (!visited[i]) { dfs(i); num++; } cout << num - 1 << endl; } return 0;}
1013. Battle Over Cities (25)