Graph/Shortest_path/Bfs_0-1.cpp

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• Last update: 2026-07-26 14:40:30+07:00

Depends on

• template.h

Code

#include "../../template.h"


// Graph

int bfs01(int s, int n, vector<vector<pii>> &g) {
    vector<int> d(n+1, INT_MAX);
    deque<int> q; 
    q.push_front(s); 
    d[s] = 0;
    while (!q.empty()){
        int u = q.front(); q.pop_front();
        for (pii edge : g[u]){
            int v = edge.fi;
            int w = edge.se;
            if (w + d[u] < d[v]){
                d[v] = w + d[u];
                if (!w) {
                    q.push_front(v);
                } else {
                    q.push_back(v);
                }
            }
        }
    }
    return d[n];
}


// Matrix 0-1

int dx[4] = {-1, 0, 0, 1};
int dy[4] = {0, -1, 1, 0};

bool isValid(pii u, int n, int m) { return u.fi >= 0 && u.fi < n && u.se >= 0 && u.se < m; }

int bfs01(vector<vector<int>> &grid, int n, int m) {
    vector<vector<int>> d(n, vector<int>(m, INT_MAX));
    deque<pii> q;
    q.push_front({0, 0});
    d[0][0] = grid[0][0];
    while (!q.empty()) {
        pii u = q.front(); q.pop_front();
        for (int i = 0; i < 4; i++) {
            pii v = {u.fi + dx[i] ,u.se + dy[i]};
            if (!isValid(v, n, m)) continue;
            int w = grid[v.fi][v.se];
            if (w + d[u.fi][u.se] < d[v.fi][v.se]) {
                d[v.fi][v.se] = w + d[u.fi][u.se];
                if (!w) q.push_front(v);
                else q.push_back(v);
            }
        }
    }
    return d[n-1][m-1];
}

#line 2 "template.h"

#include <bits/stdc++.h>

using namespace std;
 
#define ll long long
#define MOD (ll)(1e9+7)
#define all(x) (x).begin(),(x).end()
#define unique(x) x.erase(unique(all(x)), x.end())
#define INF32 ((1ull<<31)-1)
#define INF64 ((1ull<<63)-1)
#define inf (ll)1e18

#define vi vector<int>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
ll get_rand(ll r) { return uniform_int_distribution<ll>(0, r - 1)(rng); }

const int mod = 998244353;

void solve();

int main(){
    ios_base::sync_with_stdio(false);cin.tie(NULL);
    // cin.exceptions(cin.failbit);

    // int t; cin >> t;

    // while(t--)

        solve();
    cerr << "\nTime run: " << 1000 * clock() / CLOCKS_PER_SEC << "ms" << '\n';
    return 0;
}
#line 2 "Graph/Shortest_path/Bfs_0-1.cpp"

// Graph

int bfs01(int s, int n, vector<vector<pii>> &g) {
    vector<int> d(n+1, INT_MAX);
    deque<int> q; 
    q.push_front(s); 
    d[s] = 0;
    while (!q.empty()){
        int u = q.front(); q.pop_front();
        for (pii edge : g[u]){
            int v = edge.fi;
            int w = edge.se;
            if (w + d[u] < d[v]){
                d[v] = w + d[u];
                if (!w) {
                    q.push_front(v);
                } else {
                    q.push_back(v);
                }
            }
        }
    }
    return d[n];
}


// Matrix 0-1

int dx[4] = {-1, 0, 0, 1};
int dy[4] = {0, -1, 1, 0};

bool isValid(pii u, int n, int m) { return u.fi >= 0 && u.fi < n && u.se >= 0 && u.se < m; }

int bfs01(vector<vector<int>> &grid, int n, int m) {
    vector<vector<int>> d(n, vector<int>(m, INT_MAX));
    deque<pii> q;
    q.push_front({0, 0});
    d[0][0] = grid[0][0];
    while (!q.empty()) {
        pii u = q.front(); q.pop_front();
        for (int i = 0; i < 4; i++) {
            pii v = {u.fi + dx[i] ,u.se + dy[i]};
            if (!isValid(v, n, m)) continue;
            int w = grid[v.fi][v.se];
            if (w + d[u.fi][u.se] < d[v.fi][v.se]) {
                d[v.fi][v.se] = w + d[u.fi][u.se];
                if (!w) q.push_front(v);
                else q.push_back(v);
            }
        }
    }
    return d[n-1][m-1];
}

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