bzoj 1102

思路：用dfs 会爆栈，巨坑，要用bfs。

#include<bits/stdc++.h>
#define LL long long
#define fi first
#define se second
#define mk make_pair
#define pii pair<int,int>
#define piii pair<int, pair<int,int> >

using namespace std;

const int N = 1000 + 10;
const int M = 10 + 7;
const int inf = 0x3f3f3f3f;
const LL INF = 0x3f3f3f3f3f3f3f3f;
const int mod = 1e9 + 7;
const double eps = 1e-7;

int n, ans1, ans2, s[N][N], mx[N][N], mn[N][N];
int dx[] = {1, -1, 0, 0, 1, 1, -1, -1};
int dy[] = {0, 0, 1, -1, 1, -1, 1, -1};

bool vis[N][N];

bool bfs1(int sx, int sy) {
    queue<pii> que;
    vis[sx][sy] = true;

    que.push(mk(sx, sy));

    bool flag = true;
    while(!que.empty()) {
        pii u = que.front(), v;
        que.pop();
        if(mx[u.fi][u.se] > s[u.fi][u.se]) {
            flag = false;
        }

        for(int i = 0; i < 8; i++) {
            v.fi = u.fi + dx[i];
            v.se = u.se + dy[i];
            if(v.fi < 1 || v.fi > n || v.se < 1 || v.se > n || vis[v.fi][v.se] || s[v.fi][v.se] != s[u.fi][u.se])
                continue;
            vis[v.fi][v.se] = true;
            que.push(v);
        }
    }
    return flag;
}

bool bfs2(int sx, int sy) {
    queue<pii> que;
    vis[sx][sy] = true;

    que.push(mk(sx, sy));

    bool flag = true;
    while(!que.empty()) {
        pii u = que.front(), v;
        que.pop();
        if(mn[u.fi][u.se] < s[u.fi][u.se]) {
            flag = false;
        }

        for(int i = 0; i < 8; i++) {
            v.fi = u.fi + dx[i];
            v.se = u.se + dy[i];
            if(v.fi < 1 || v.fi > n || v.se < 1 || v.se > n || vis[v.fi][v.se] || s[v.fi][v.se] != s[u.fi][u.se])
                continue;
            vis[v.fi][v.se] = true;
            que.push(v);
        }
    }

    return flag;
}

int main() {
    scanf("%d", &n);
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            scanf("%d", &s[i][j]);
            mx[i][j] = mn[i][j] = s[i][j];
        }
    }

    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            for(int k = 0; k < 8; k++) {
                int x = i + dx[k];
                int y = j + dy[k];
                if(x < 1 || x > n || y < 1 || y > n)
                    continue;

                mx[i][j] = max(mx[i][j], s[x][y]);
                mn[i][j] = min(mn[i][j], s[x][y]);
            }
        }
    }

    ans1 = 0, ans2 = 0;
    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            if(!vis[i][j]) {
                ans1 += bfs1(i, j);
            }
        }
    }

    memset(vis, false, sizeof(vis));

    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= n; j++) {
            if(!vis[i][j]) {
                ans2 += bfs2(i, j);
            }
        }
    }

    printf("%d %d\n", ans1, ans2);
    return 0;
}

原文地址：https://www.cnblogs.com/CJLHY/p/9191143.html