一看到题目用最短的路径，首先想到要用BFS，其次，要求记录路径，我们可以在状态里面添加字符串变量（也即我的代码里面的ans，每到达一个地点字符串ans就加一个方向，即‘D’,'L','R','U'中的任意一个），当到达右下角那个点时即可输出答案。
#include <iostream>
#include <queue>
#include <string>
using namespace std;struct node{int x, y;string ans;node(int _x, int _y, string _ans) {x = _x, y = _y;ans = _ans;}
};bool mp[31][51];
bool d[31][51];
bool vis[31][51];int dir[4][2] = {
{1, 0}, {0, -1}, {0, 1}, {-1, 0}};
char td[4] = {'D', 'L', 'R', 'U'};
bool in (int x, int y) {return 0 <= x && x < 30 && 0 <= y && y < 50;
}
int main() {for (int i = 0; i < 30; i++) {scanf("%s", mp[i]);}queue<node> q;q.push(node(0, 0, ""));while (!q.empty()) {node first = q.front();q.pop();if (first.x == 29 && first.y == 49) {cout << first.ans << endl;break;}for (int i = 0; i < 4; i++) {int tx = first.x + dir[i][0];int ty = first.y + dir[i][1];if (in(tx, ty) && mp[tx][ty] != '1' && !vis[tx][ty]) {vis[tx][ty] = true;q.push(node(tx, ty, first.ans + td[i]));vis[tx][tx] = false;}}}return 0;
}
Input：
00010000100100000101001010101110100010101010000101
11100100101001001000010000010101010100100100010100
00000010000000101011001111010001100000101010100011
10101010011100001000011000010110011110110100001000
10101010100001101010100101000010100000111011101001
10000000101100010000101100101101001011100000000100
10101001000000010100100001000100000100011110101001
00101001010101101001010100011010101101110000110101
11001010000100001100000010100101000001000111000010
00001000110000110101101000000100101001001000011101
10100101000101000000001110110010110101101010100001
00101000010000110101010000100010001001000100010101
10100001000110010001000010101001010101011111010010
00000100101000000110010100101001000001000000000010
11010000001001110111001001000011101001011011101000
00000110100010001000100000001000011101000000110011
10101000101000100010001111100010101001010000001000
10000010100101001010110000000100101010001011101000
00111100001000010000000110111000000001000000001011
10000001100111010111010001000110111010101101111000Output：
DDDDRRURRRRRRDRRRRDDDLDDRDDDDDDDDDDDDRDDRRRURRUURRDDDDRDRRRRRRDRRURRDDDRRRRUURUUUUUUULULLUUUURRRRUULLLUUUULLUUULUURRURRURURRRDDRRRRRDDRRDDLLLDDRRDDRDDLDDDLLDDLLLDLDDDLDDRRRRRRRRRDDDDDDRR