Codeforces 1130 Connect——水题

康复训练

#include <bits/stdc++.h>
using namespace std;
const int maxn = 100;
int n;
int r1, c1, r2, c2;
char str[maxn];
int G[maxn][maxn];
int tot;
bool vis[maxn][maxn];
typedef pair<int , int> P;
vector<P> vec[maxn*maxn];
int s, t;
const int dx[] = {-1, 1, 0, 0};
const int dy[] = {0, 0, -1, 1};
const int INF = 0x3f3f3f3f;
void dfs(int x, int y) {
    vis[x][y] = 1;
    vec[tot].push_back(make_pair(x, y));
    if (x == r1 && y == c1) {
        s = tot;
    }
    else if (x == r2 && y == c2) {
        t = tot;
    }
    for (int i = 0; i < 4; i++) {
        int xx = x + dx[i], yy = y + dy[i];
        if (1 <= xx && xx <= n && 1 <= yy && yy <= n && G[xx][yy] == 0 && !vis[xx][yy]) {
            dfs(xx, yy);
        }
    }
}
int dis(int x1, int y1, int x2, int y2) {
    return (x2-x1)*(x2-x1) + (y2-y1)*(y2-y1);
}
int main() {
    scanf("%d", &n);
    scanf("%d %d %d %d", &r1, &c1, &r2, &c2);
    getchar();
    for (int i = 1; i <= n; i++) {
        gets(str);
        for (int j = 1; j <= n; j++) {
            G[i][j] = str[j-1] - '0';
        }
    }
    if (r1 == r2 && c1 == c2) {
        printf("0\n");
        return 0;
    }
    tot = 0;
    memset(vis, 0, sizeof(vis));
    for (int i = 1; i <= n * n; i++) {
        vec[i].clear();
    }
    s = t = 1;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= n; j++) {
            if (G[i][j] == 0 && !vis[i][j]) {
                ++tot;
                dfs(i, j);
            }
        }
    }
    if (s == t) {
        printf("0\n");
    }
    else {
        int ans = INF;
        for (int i = 0; i < vec[s].size(); i++) {
            for (int j = 0; j < vec[t].size(); j++) {
                ans = min(ans, dis(vec[s][i].first, vec[s][i].second, vec[t][j].first, vec[t][j].second));
            }
        }
        printf("%d\n", ans);
    }
    return 0;
}