HDU 1010 Tempter of the Bone（DFS+奇偶剪枝）

第一次用奇偶剪纸，记录一下吧

#include <iostream>#include <stdio.h>#include <string.h>#include <algorithm>#include <math.h>using namespace std;class NODE{public:        NODE(int x,int y,int times):x(x),y(y),times(times){};    NODE(){};    NODE(const NODE &a)    {        x=a.x;        y=a.y;        times=a.times;    }    bool operator == (const NODE &a)    {        if(x==a.x&&y==a.y&×==a.times)            return true;        else            return false;    }    int x,y,times;};int row,col,times;NODE END;const char wall ='X';const char road ='.';const char start ='S';const char end = 'D';char map[10][10];int s_x,s_y;int dir_x[]={0,1,0,-1};int dir_y[]={1,0,-1,0};bool canThrough(int x,int y){    if(x>=0&&x<row&&y>=0&&y<col&&map[x][y]==road)        return true;    else        return false;}bool _find;void dfs(int x,int y,int t){    if(_find==true|| t>=times)        return ;    int cut=times-t-abs(x-END.x)-abs(y-END.y);    if(cut<0 || cut&1 )        return ;    for(int i=0;i<4;i++)    {        int now_x=x+dir_x[i];        int now_y=y+dir_y[i];        int tt=t+1;        if(NODE(now_x,now_y,tt)==END)        {            _find=true;            return;        }        if(canThrough(now_x,now_y))        {            map[now_x][now_y]=wall;            dfs(now_x,now_y,tt);            map[now_x][now_y]=road;        }    }}int main(){    //freopen("in.txt","r",stdin);    while(cin>>row>>col>>times,row,col,times)    {        _find=false;        for(int i=0;i<row;i++)        {            for(int j=0;j<col;j++)            {                cin>>map[i][j];                if(map[i][j]==start)                {                    s_x=i;                    s_y=j;                    continue;                }                if(map[i][j]==end)                {                    END=NODE(i,j,times);                    continue;                }            }        }        dfs(s_x,s_y,0);        if(_find)            cout<<"YES"<<endl;        else            cout<<"NO"<<endl;    }    return 0;}