HDU 1180 诡异的楼梯(bfs+判断)

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注意：

1，楼梯不会连续出现，避免考虑很多楼梯连着的复杂情况。
2，存在等在楼梯前，然后走楼梯的情况。
3，考虑过了楼梯直接就是终点的情况。

#include <iostream>#include <cstdio>#include <string.h>#include <queue>using namespace std;char s[22];int sx,sy;int v[30][30];int d[4][2] = {{-1,0},{1,0},{0,-1},{0,1}};//方向分量struct node{    int x,y,t;    int flag = 0;    node(){}    node(int x,int y,int t,int flag){       this->x = x,this->y = y,this->t = t,this->flag = flag;    }};int bfs(int ii,int jj){    node temp(ii,jj,0,0);    int ans = -100;    queue<node> q;    q.push(temp);    while(!q.empty()){        temp = q.front();        q.pop();        if(temp.flag == 1){            temp.t++;            temp.flag = 0;            if(v[temp.x][temp.y] == 666)                return temp.t;            q.push(temp);            continue;        }        else if(v[temp.x][temp.y] == 666)            return temp.t;        for(int i = 0;i < 4;i++){            int a = temp.x + d[i][0],b = temp.y + d[i][1];            if(v[a][b] == 1){                v[a][b] = 0;                q.push(node(a,b,temp.t+1,0));            }            else if(v[a][b] == 2 || v[a][b] == -2){// 此格是楼梯                int t1 = v[a][b];                if(temp.t & 1)                    t1 = -v[a][b];                int aa = a + d[i][0],bb = b + d[i][1];                int &t2 = v[aa][bb];                if(t1 == 2 && t2 != 0){                    if(t2 == 1)                        t2 = 0;                    if(i < 2){// 方向为竖                        q.push(node(aa,bb,temp.t+1,0));                    }                    else{                        q.push(node(aa,bb,temp.t+1,1));                    }                }                else if(t1 == -2 && t2 != 0){                    if(t2 == 1)                        t2 = 0;                    if(i > 1){// 方向为横                        q.push(node(aa,bb,temp.t+1,0));                    }                    else{                        q.push(node(aa,bb,temp.t+1,1));                    }                }            }            else if(v[a][b] == 666){                return temp.t+1;            }        }    }    return -1;}int main(){    int ans;    int m,n;    while(scanf("%d%d",&m,&n) != EOF){        memset(v,0,sizeof(v));        for(int i = 1;i <= m;i++){            scanf("%s",s);            for(int j = 0;j < n;j++){                if(s[j] == 'S'){                    sx = i,sy = j+1;                    v[i][j+1] = 0;                }                else if(s[j] == 'T'){                    v[i][j+1] = 666;                }                else if(s[j] == '.'){                    v[i][j+1] = 1;                }                else if(s[j] == '|'){                    v[i][j+1] = 2;                }                else if(s[j] == '-'){                    v[i][j+1] = -2;                }            }        }        ans = bfs(sx,sy);        printf("%d\n",ans);    }    return 0;}

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