https://ac.nowcoder.com/acm/contest/330/C

C++版本一

std

题解：

搜索，模拟

BFS 求最短路。
注意点是状态要三维。d[x][y][0/1]表示在(x, y)处，属性为水/火的最短路。
按题意模拟，分类讨论转移即可。

#include <bits/stdc++.h>
using namespace std;
 
typedef pair<pair<int, int>, int> Node;
const int maxn = 105;
char maze[maxn][maxn];
int vis[maxn][maxn][2];
int tx[] = {-1, 0, 1, 0};
int ty[] = {0, -1, 0, 1};
 
int bfs(const pair<int, int>& S,
        const pair<int, int>& T,
        int n, int m)
{
    memset(vis, -1, sizeof(vis));
    queue<Node> q;
    q.push({S, 0});
    vis[S.first][S.second][0] = 0;
    while (!q.empty())
    {
        Node tmp = q.front();
        q.pop();
        int x = tmp.first.first, y = tmp.first.second;
        bool p = tmp.second;
        for (int i = 0; i < 4; i++)
        {
            int nx = x + tx[i], ny = y + ty[i];
            if (nx < 0 || ny < 0 || nx >= n || ny >= m) continue;
            if (~vis[nx][ny][p]) continue;
            if (maze[nx][ny] == '#') continue;
            if (p && maze[nx][ny] == '~') continue;
            if (!p && maze[nx][ny] == 'w') continue;
            vis[nx][ny][p] = vis[x][y][p] + 1;
            pair<int, int> nxt = {nx, ny};
            if (nxt == T) return vis[nx][ny][p];
            q.push({nxt, p});
        }
        if (maze[x][y] == '@' && vis[x][y][p ^ 1] == -1)
        {
            vis[x][y][p ^ 1] = vis[x][y][p] + 1;
            q.push({tmp.first, p ^ 1});
        }
    }
    return -1;
}
 
int main()
{
    int n, m;
    pair<int, int> S, T;
    scanf("%d%d", &n, &m);
    for (int i = 0; i < n; i++)
        scanf("%s", maze[i]);
    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++)
            if (maze[i][j] == 'S')
                S = {i, j};
            else if (maze[i][j] == 'T')
                T = {i, j};
 
    int ans = bfs(S, T, n, m);
    printf("%d\n", ans);
 
    return 0;
}

扫一扫，把题目装进口袋

C++版本二

BFS

/*
*@Author:   STZG
*@Language: C++
*/
#include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
//#define DEBUG
#define RI register int
using namespace std;
typedef long long ll;
//typedef __int128 lll;
const int N=1000+10;
const int MOD=1e9+7;
const double PI = acos(-1.0);
const double EXP = 1E-8;
const int INF = 0x3f3f3f3f;
int t,n,m,k,sx,sy,ex,ey;
int ans,cnt,flag,temp;
int dir[][2]={0,1,1,0,0,-1,-1,0};
char str[N][N];
bool vis[N][N][2];
struct node{
    int x,y,f,step;
}s,tmp,f;
int main()
{
#ifdef DEBUG
	freopen("input.in", "r", stdin);
	//freopen("output.out", "w", stdout);
#endif
    scanf("%d%d",&n,&m);
    //scanf("%d",&t);
    //while(t--){}
    for(int i=1;i<=n;i++){
        scanf("%s",str[i]+1);
        for(int j=1;j<=m;j++){
            if(str[i][j]=='S')
                sx=i,sy=j;
            if(str[i][j]=='T')
                ex=i,ey=j;
        }
    }
    queue<node>q;
    s.x=sx;
    s.y=sy;
    s.f=0;
    s.step=0;
    vis[sx][sx][0]=1;
    q.push(s);
    while(!q.empty()){
        f=q.front();
        q.pop();
        //cout<<f.x<<" "<<f.y<<endl;
        if(f.x==ex&&f.y==ey){
            flag=1;
            break;
        }
        f.step++;
        tmp=f;
        if(str[f.x][f.y]=='@'){
            tmp.f=!tmp.f;
            if(vis[tmp.x][tmp.y][tmp.f]==0){
                vis[tmp.x][tmp.y][tmp.f]=1;
                q.push(tmp);
            }
        }
        tmp=f;
        for(int i=0;i<4;i++){
            tmp.x=f.x+dir[i][0];
            tmp.y=f.y+dir[i][1];
            if(tmp.x<1||tmp.y<1||tmp.x>n||tmp.y>m)
                continue;
            if(str[tmp.x][tmp.y]=='#')
                continue;
            if(vis[tmp.x][tmp.y][tmp.f])
                continue;
            if(str[tmp.x][tmp.y]=='~'&&tmp.f==1)
                continue;
            if(str[tmp.x][tmp.y]=='w'&&tmp.f==0)
                continue;
            vis[tmp.x][tmp.y][tmp.f]=1;
            q.push(tmp);
        }
    }
    if(flag)
        cout<<f.step<<endl;
    else
        cout<<-1<<endl;
    //cout << "Hello world!" << endl;
    return 0;
}