算法竞赛入门经典 8.3.1棋盘覆盖问题

#include <cstring>#include <cstdio>#include <cstdlib>using namespace std;const int MAX = 32;int n;int A[MAX][MAX];int st;void print(){    for(int i=0; i<n; i++) {        for(int j=0; j<n; j++) {            printf("%3d", A[i][j]);        }        printf("\n");    }    printf("\n");}void dfs(int x, int y, int w){    if(w == 1) {        return;    }    int i, j;    int found = 0;    for(i=x; i<x+w; i++) {        for(j=y; j<y+w; j++) {            if(A[i][j] != 0) {                found = 1;                break;            }        }        if(found) break;    }    int mx = x+w/2, my = y+w/2;    int bx = i < mx;    int by = j < my;    if(bx) {        A[mx][my-1] = A[mx][my] = st;        if(by) A[mx-1][my] = st;        else A[mx-1][my-1] = st;    } else {        A[mx-1][my] = A[mx-1][my-1] = st;        if(by) A[mx][my] = st;        else A[mx][my-1] = st;    }    print();    st++;    int tw = w/2;    dfs(mx-tw, my-tw, tw);    dfs(mx-tw, my, tw);    dfs(mx, my-tw, tw);    dfs(mx, my, tw);}int main(){    #ifndef ONLINE_JUDGE    freopen("in.txt", "r", stdin);    #endif    int k;    int gx, gy;    while(scanf("%d%d%d", &k, &gx, &gy) == 3) {        memset(A, 0, sizeof(A));        st = 1;        n = 1 << k;        A[gx][gy] = -1;        print();        dfs(0, 0, n);        print();    }    return 0;}