1013 Battle Over Cities

1. 题目

2. 抽象建模

图求连通分量个数

3. 方法

深度优先递归遍历

4. 注意点

无

5.代码

#include<stdio.h>
#include<string.h>

int map[1001][1001];
int visited[1001];
int need_roads[1001];

void dfs(int row, int citys){
    visited[row] = 1;
    for(int i=1;i<=citys;i++){
        if(visited[i] == 0){
            if(map[row][i] == 1){
                dfs(i, citys);
            }
        }       
    }
}

int main(){
    int citys, roads, fixs;
    int index_i, index_j;
    scanf("%d %d %d", &citys, &roads, &fixs);
    for(int i=0;i<roads;i++){
        scanf("%d %d", &index_i, &index_j);
        map[index_i][index_j] = 1;
        map[index_j][index_i] = 1;
    }
    
    int fix;
    for(int i=0;i<fixs;i++){
        memset(visited, 0, 1001*4);
        scanf("%d", &fix);
        visited[fix] = 1;
        int count = 0;
        for(int j=1;j<=citys;j++){
            if(visited[j] == 0){
                count++;
                dfs(j, citys);
            }
        }
        need_roads[i] = count - 1;
    }
    for(int i=0;i<fixs;i++){
        printf("%d\n", need_roads[i]);
    }
}

1013 Battle Over Cities

原文：https://www.cnblogs.com/d-i-p/p/11490397.html