方法粗陋，时间略长，还望指教。

#include <stdio.h> #include <stdlib.h> int mintimes=225; int nowtimes=0; void collor(int*a) {     *a?(*a=0):(*a=1); } void change(int*now,int size) {     collor(now);     collor(now+1);     collor(now-1);     collor(now+size+2);     collor(now-size-2); } void searchf(int i,int size,int*wall,int*record)//穷举第一行i~n的所有可能 {     void paint(int*wall,int n,int*record);     if(i<=size)     {         searchf(i+1,size,wall,record);         change(wall+size+2+i,size);         *(record+(size+2)+i)=1;         searchf(i+1,size,wall,record);         change(wall+size+2+i,size);         *(record+(size+2)+i)=0;     }     else         paint(wall,size,record); } void paint(int*wall,int n,int*record) {     int flag=0,i,j;     for(i=1;i<n;i++)     {         for(j=1;j<n+1;j++)         {             if(*(wall+i*(n+2)+j)==0)             {                 change(wall+(i+1)*(n+2)+j,n);                 *(record+(i+1)*(n+2)+j)=1;                 nowtimes++;             }         }     }     for(i=1;i<n+1;i++)     {         flag+=*(wall+n*(n+2)+i);         nowtimes+=*(record+(n+2)+i);     }     if(flag==n&&nowtimes<mintimes)         mintimes=nowtimes;     for(i=2;i<=n;i++)     {         for(j=1;j<n+1;j++)         {             if(*(record+i*(n+2)+j)==1)             {                 change(wall+i*(n+2)+j,n);                 *(record+i*(n+2)+j)=0;             }         }     }     nowtimes=0; } int main() {     int n,i,j;     scanf(“%d”,&n);     int paint[n+2][n+2],record[n+2][n+2];     for(i=1;i<n+1;i++)         for(j=1;j<n+1;j++)             record[i][j]=0;     char wall[n+2][n+2];     for(i=1;i<n+1;i++)     {         scanf(“%s”,&wall[i][1]);         for(j=1;j<n+1;j++)             (wall[i][j]==’w’)?(paint[i][j]=0):(paint[i][j]=1);     }     searchf(1,n,paint[0],record[0]);     (mintimes>200)?(printf(“inf”)):(printf(“%d”,mintimes));     return 0; }