最后3个点WA了……

#include<iostream>
#include<cstdio>
#include<cmath>
#include<string>
#include<cstring>
#include<algorithm>
#include<bits/stdc++.h>
using namespace std;
struct node {
	long long x1, y1, z1;
} t1, s;
queue<node> q;
long long m, t[1005], x[1005], y[1005], a[400][400], b[400][400];
int dx[] = {-1, 1, 0, 0, 0};
int dy[] = {0, 0, -1, 1, 0};
void BFS(int xx, int yy, int zz) {
	t1 = {xx, yy, zz};
	q.push(t1);
	while(!q.empty()) {
		t1 = q.front();
		q.pop();
		for(int i = 0; i < 4; i++) {
			int xxx = t1.x1 + dx[i];
			int yyy = t1.y1 + dy[i];
			if(xxx >= 0 && yyy >= 0 && b[xxx][yyy] == 0) {
				b[xxx][yyy] = 1;
				if(c[xxx][yyy] == 0) {
					printf("%d", t1.z1 + 1);
					exit(0);
				} else {
					s = {xxx, yyy, t1.z1 + 1};
					if(s.z1 < a[xxx][yyy] - 1) {
						q.push(s);
					}
				}
			}
		}
	}
}
int main() {
	scanf("%d", &m);
	b[0][0] = 1;
	for(int i = 0; i < m; i++) {
		scanf("%d %d %d", &x[i], &y[i], &t[i]);
		if(a[x[i]][y[i]] == 0) {
			a[x[i]][y[i]] = t[i] + 1;
		}else{
			if(a[x[i]][y[i]] > t[i] + 1){
				a[x[i]][y[i]] = t[i] + 1;
			}
		}
		if(a[x[i]][y[i]] != 0){
			c[x[i]][y[i]] = 1;
		}
		if(x[i] - 1 >= 0) {
			if(a[x[i] - 1][y[i]] == 0){
				a[x[i] - 1][y[i]] = t[i] + 1;
			}else{
				if(a[x[i] - 1][y[i]] > t[i] + 1){
					a[x[i] - 1][y[i]] = t[i] + 1;
				}
			}
		}
		if(a[x[i] - 1][y[i]] != 0){
			c[x[i] - 1][y[i]] = 1;
		}
		if(y[i] - 1 >= 0) {
			if(a[x[i]][y[i] - 1] == 0){
				a[x[i]][y[i] - 1] = t[i] + 1;
			}else{
				if(a[x[i]][y[i] - 1] > t[i] + 1){
					a[x[i]][y[i] - 1] = t[i] + 1;
				}
			}
		}
		if(a[x[i]][y[i] - 1] != 0){
			c[x[i]][y[i] - 1] = 1;
		}
		if(a[x[i] + 1][y[i]] == 0) {
			a[x[i] + 1][y[i]] = t[i] + 1;
		}else{
			if(a[x[i] + 1][y[i]] > t[i] + 1){
				a[x[i] + 1][y[i]] = t[i] + 1;
			}
		}
		if(a[x[i] + 1][y[i]] != 0){
			c[x[i] + 1][y[i]] = 1;
		}
		if(a[x[i]][y[i] + 1] == 0) {
			a[x[i]][y[i] + 1] = t[i] + 1;
		}else{
			if(a[x[i]][y[i] + 1] > t[i] + 1){
				a[x[i]][y[i] + 1] = t[i] + 1;
			}
		}
		if(a[x[i]][y[i] + 1] != 0){
			c[x[i]][y[i] + 1] = 1;
		}
	}
	BFS(0, 0, 0);
	printf("-1");
	return 0;
}
//⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⢸⣿⣿⣿⠀⣼⣿⣿⣦⡀
//⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⠀⠀⠀⠀⢸⣿⣿⡟⢰⣿⣿⣿⠟⠁
//⠀⠀⠀⠀⠀⠀⠀⢰⣿⠿⢿⣦⣀⠀⠘⠛⠛⠃⠸⠿⠟⣫⣴⣶⣾⡆⠀⠀⠀
//⠀⠀⠀⠀⠀⠀⠀⠸⣿⡀⠀⠉⢿⣦⡀⠀⠀⠀⠀⠀⠀⠛⠿⠿⣿⠃⠀⠀⠀
//⠀⠀⠀⠀⠀⠀⠀⠀⠙⢿⣦⠀⠀⠹⣿⣶⡾⠛⠛⢷⣦⣄⠀
//⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⣿⣧⠀⠀⠈⠉⣀⡀⠀⠀⠙⢿⡇
//⠀⠀⠀⠀⠀⠀⢀⣠⣴⡿⠟⠋⠀⠀⢠⣾⠟⠃⠀⠀⠀⢸⣿⡆
//⠀⠀⠀⢀⣠⣶⡿⠛⠉⠀⠀⠀⠀⠀⣾⡇⠀⠀⠀⠀⠀⢸⣿⠇
//⢀⣠⣾⠿⠛⠁⠀⠀⠀⠀⠀⠀⠀⢀⣼⣧⣀⠀⠀⠀⢀⣼⠇
//⠈⠋⠁⠀⠀⠀⠀⠀⠀⠀⠀⢀⣴⡿⠋⠙⠛⠛⠛⠛⠛⠁
//⠀⠀⠀⠀⠀⠀⠀⠀⠀⣀⣾⡿⠋⠀
//⠀⠀⠀⠀⠀⠀⠀⠀⢾⠿⠋⠀