242C - King's Path - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;
const long long int N = 1e4;
const long long int INF = 1e9+10;
const long long int row = 1e9;
const long long int col = 1e9;

pair<int, int> src, dest;

//bool vis[N][N] = {false};
map <pair<int,int>, bool> vis;
//long long int level[N][N];
map <pair<int,int>, int> level;
map <pair<int,int>, bool> allowed;

bool isvalid(int x, int y){
    return x>=0 and y >=0 and x <= row and y <= col and allowed[{x, y}];
}

vector <pair<int, int>> movements = {
    {1,0}, {-1,0}, {0,1}, {0,-1},
    {-1, -1}, {1, 1}, {1,-1}, {-1,1}
};


int bfs(pair<int, int>p1, pair<int, int> p2){
    int source_x = p1.first;
    int source_y = p1.second;
    int dest_x = p2.first;
    int dest_y = p2.first;
    level[{source_x, source_y}] = 0;
    vis[{source_x, source_y}] = true;
    queue <pair<int, int>> q;
    q.push({source_x, source_y});
    while(!q.empty()){
        pair <int, int> p = q.front();
        q.pop();
        int x = p.first;
        int y = p.second;
        bool check = false;
        /*
        for(auto move:movements)
        {
            int check_x = move.first + x;
            int check_y = move.first + y;
            check = check | isvalid(check_x, check_y);
        }
        if(!check){
            return -1;
        }*/
        
        for(auto move: movements){
            int newx = move.first + x;
            int newy = move.second + y;
            if(!isvalid(newx, newy)) continue;
            if(!vis[{newx, newy}]){
                q.push({newx, newy});
                level[{newx,newy}] = level[{x,y}] +1;
                vis[{newx,newy}] = true;
                if(newx == dest.first and newy == dest.second){
                    return level[{newx, newy}];
                }
            }
        }
    }
    return level[{dest.first, dest.second}];
}




int main(){
    long long int s1, s2, d1, d2;
    cin >> s1 >> s2 >> d1 >> d2;
    
    src.first = s1;
    src.second = s2;
    dest.first = d1;
    dest.second = d2;
    int n; cin >> n;
    for(int i = 0; i < n; i++){
        long long int r, a, b;
        cin >> r >> a >> b;
        for(int j = a;j <= b; j++){
            allowed[{r, j}] = true;
        }
    }
    int ans = bfs(src, dest);
    if(ans == 0){
        if(src.first == dest.first and src.second == dest.second){
            cout << 0 << endl;
        }else{
            cout << -1 << endl;
        }
    }
    else
    {
        cout << ans << endl;
    }
}