AHU-61 Lake Counting (并查集）

来源：互联网发布：versions 1.7 for mac 编辑：程序博客网时间：2024/06/02 08:41

这里写图片描述

简单并查集

Code

#include<bits/stdc++.h>using namespace std;const int MAXN = 10000 + 10;const int dx[] = {1, -1, 0, 0, 1, -1, 1, -1};const int dy[] = {0, 0, 1, -1, 1, -1, -1, 1};int node[MAXN], pre[MAXN];int find(int x) {    return pre[x] == x ? x : pre[x] = find(pre[x]);}void join(int x, int y) {    int xx = find(x);    int yy = find(y);    if (xx != yy) {        pre[yy] = xx;    }}int main() {    int n, m, z;    while(~scanf("%d%d", &n, &m)) {        getchar();        char ch;        for (int i = 0; i < n; ++i) {            for (int j = 0; j <= m; ++j) { //j多循环一次读换行                scanf("%c", &ch);                z = i * m + j;                if (ch == '.') node[z] = 0;                else if (ch == 'W') node[z] = 1;                pre[z] = z;            }        }        for (int i = 0; i < n*m; ++i) {            if (node[i] == 0) continue;            int x = i / m, y = i % m;            for (int j = 0; j < 8; ++j) {                int nx = x + dx[j], ny = y + dy[j];                if (nx < 0 || nx >= n || ny < 0 || ny >= m) continue;                int nz = nx * m + ny;                if (node[nz] == 1)                    join(i, nz);            }        }        set<int> root;        for (int i = 0; i < n*m; ++i) {            if (node[i] == 0) continue;            int nroot = find(i);            root.insert(nroot);        }        printf("%d\n", root.size());    }    return 0;}

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