我的思路是在由药、起点、终点构成的小图上面做操作以优化时间。我先写了一版DFS代码，T了，但是在小图上面跑DFS时加上一个判断能量的数组（只是单纯存了一个点的最大能量）优化就过了。

但是能量数组写成了尽量让到达这个点的能量小的代码，跑的飞快，全AC，为什么？

Code:

#include <algorithm>
#include <iostream>
#include <cstring>
#include <vector>
#include <queue>
#include <stack>
#include <cmath>
#include <list>
#include <set>
#include <map>
#include <time.h>
using namespace std;
int h, w, a[300][300];
char m[300][300];
int n;
int dis[400][400];
int x[400], y[400];
int dx[4] = {0, 0, -1, 1}, dy[4] = {-1, 1, 0, 0};
void bfs(int idx) {
	int dist[300][300];
	memset(dist, 0x3f, sizeof(dist));
	dist[x[idx]][y[idx]] = 0;
	queue<int> q;
	q.push(x[idx]);
	q.push(y[idx]);
	while (q.size()) {
		int nowx = q.front();
		q.pop();
		int nowy = q.front();
		q.pop();
		for (int i = 0; i < 4; i++) {
			int nx = nowx + dx[i], ny = nowy + dy[i];
			if (nx >= 1 && nx <= h && ny >= 1 && ny <= w && dist[nx][ny] == 0x3f3f3f3f && m[nx][ny] != '#') {
				dist[nx][ny] = dist[nowx][nowy] + 1;
				q.push(nx);
				q.push(ny);
			}
		}
	}
	for (int i = 1; i <= n + 2; i++) {
		dis[idx][i] = dist[x[i]][y[i]];
	}
}
bool vis[300][300];
int dis1[400];
void dfs(const int u, int t) {
	if (t < dis1[u]) dis1[u] = t;
	else return;
	int p = x[u], q = y[u];
	vis[x[u]][q] = 1;
	if (p == x[2] && q == y[2]) {
		cout << "Yes";
		exit(0);
	}
	int tmp = a[p][q];
	if (t < a[p][q] && a[p][q]) {
		t = a[p][q], a[p][q] = 0;
	}
	for (int i = 1; i <= n + 2; i++) {
		if ((x[i] != p || y[i] != q) && !vis[x[i]][y[i]] && t >= dis[u][i]) {
			t -= dis[u][i];
			dfs(i, t);
			t += dis[u][i];
		}
	}
	a[p][q] = tmp;
	vis[p][q] = 0;
}
int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> h >> w;
	for (int i = 1; i <= h; i++) {
		for (int j = 1; j <= w; j++) {
			cin >> m[i][j];
			if (m[i][j] == 'S') {
				x[1] = i, y[1] = j;
			}
			if (m[i][j] == 'T') {
				x[2] = i, y[2] = j;
			}
		}
	}
	cin >> n;
	for (int i = 1; i <= n; i++) {
		int r, c, e;
		cin >> r >> c >> e;
		a[r][c] = e;
		x[i + 2] = r, y[i + 2] = c;
	}
	for (int i = 1; i <= n * 2; i++) {
		bfs(i);
	}
	memset(dis1, 0x3f, sizeof(dis1));
	dfs(1, 0);
	cout << "No";
	return 0;
}