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Submission #601548

# Submission time Handle Problem Language Result Execution time Memory
601548 2022-07-22T07:44:30 Z nguyentu Valley (BOI19_valley) C++14
100 / 100
 282 ms 53668 KB 
#include <bits/stdc++.h>

#pragma GCC target("avx2")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")

using namespace std;

#define ii pair<int , int>  
#define iv pair<ii , ii>
#define iii pair<int , ii>
#define fi first
#define se second
#define int long long
const int inf = 1e18 + 7;
const int MAX_N = 1e5 + 7;
const int MOD = 1e9 + 7;

int ti[MAX_N] , to[MAX_N];
vector<ii> adj[MAX_N];
int H[MAX_N];
int P[MAX_N][19];
int C[MAX_N][19];
int f[MAX_N];
int g[MAX_N];
int d[MAX_N];   
int vis[MAX_N];
int check[MAX_N];
int timeDFS = 0;
int n , s , q , e;
vector<ii> seg;

void DFS(int u , int father) {
    P[u][0] = father;
    ti[u] = ++timeDFS;
    for (auto edge : adj[u]) {
        int v , w; tie(v , w) = edge;
        if (v != father) {
            H[v] = H[u] + 1;
            d[v] = d[u] + w;
            DFS(v , u);
        }
    }
    to[u] = ++timeDFS;
}

void DFS1(int u , int father) {
    if (check[u]) g[u] = d[u];
    for (auto edge : adj[u]) {
        int v , w; tie(v , w) = edge;
        if (v != father) {
            DFS1(v , u);        
            g[u] = min(g[u] , g[v]);    
        }
    }
}

void DFS2(int u , int father) {
    if (father != -1) { 
        C[u][0] = f[father]; 
    }
    for (auto edge : adj[u]) {
        int v , w; tie(v , w) = edge;
        if (v != father) {
            DFS2(v , u);        
        }
    }
}

void buildtable() {
	for (int u = 1 ; u <= n ; u++) {
		for (int k = 1 ; k < 19 ; k ++) {
			P[u][k] = -1;
            C[u][k] = inf;
		}
	}
	for (int k = 1 ; k < 19 ;k++) {
		for (int u = 1 ; u <= n ; u++) {
			if (P[u][k - 1] != -1){
				P[u][k] = P[P[u][k - 1]][k - 1];
				C[u][k] = min(C[u][k - 1] , C[P[u][k - 1]][k - 1]);
			}
		}
	}
}

int LCA(int u , int v) {
	if (H[u] < H[v]) {
		swap(u , v);
	}
	int ans = inf;
	while (H[u] > H[v]) {
		for (int k = 18 ; k >= 0 ; k --) {
			if (P[u][k] != -1 && H[P[u][k]] >= H[v]) {
				ans = min(ans , C[u][k]);
				u = P[u][k];
				break;
			}
		}
	}	
	if (u == v) return ans;
	while (true) {
		bool found = false;
		for (int k = 18 ; k >= 0 ; k --) {
			if (P[u][k] != 1 && P[v][k] != -1 && P[u][k] != P[v][k]) {
                ans = min({ans , C[u][k] , C[v][k]});
				u = P[u][k];
				v = P[v][k];
				found = true;
				break;
			}
		}
		if (!found) {
			break;
		}
	}
    ans = min({ans , C[u][0] , C[v][0]});
	return ans;
}

signed main() {
    ios_base::sync_with_stdio(0); cin.tie(NULL); cout.tie(NULL);
    cin >> n >> s >> q >> e;
    for (int i = 1 ; i < n ; i++) {
        int u , v , w; cin >> u >> v >> w;
        adj[u].push_back(ii(v , w));
        adj[v].push_back(ii(u , w)); 
        seg.push_back(ii(u , v));   
    }
    for (int i = 1 ; i <= n ; i++) {
        g[i] = inf;
    }
    for (int i = 1 ; i <= s ; i++) {
        int x; cin >> x;
        check[x] = true;
    }
    C[e][0] = inf;
    DFS(e , -1);
    DFS1(e , -1);
    for (int i = 1 ; i <= n ; i++) {
        if (g[i] != inf) 
            f[i] = -2*d[i] + g[i];
        else f[i] = inf;
    }
    DFS2(e , -1);
    buildtable();
    for (int i = 1 ; i <= q ; i++) {
        int I , R; cin >> I >> R;
        int u , v; tie(u , v) = seg[I - 1];
        if (H[u] < H[v]) swap(u , v);
        if(ti[u] <= ti[R] && to[R] <= to[u]) {
            int x = LCA(u , R);
            if (x == inf && f[R] == inf) {
                cout << "oo" << '\n';
            }
            else cout << min(d[R] + x , d[R] + f[R]) << '\n';
        }
        else {
            cout << "escaped" << '\n';
        }
    }
    return 0;
}

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2772 KB Output is correct
2 Correct 3 ms 2844 KB Output is correct
3 Correct 3 ms 2820 KB Output is correct
4 Correct 5 ms 2868 KB Output is correct

Subtask #2
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2772 KB Output is correct
2 Correct 3 ms 2844 KB Output is correct
3 Correct 3 ms 2820 KB Output is correct
4 Correct 5 ms 2868 KB Output is correct
5 Correct 2 ms 3156 KB Output is correct
6 Correct 3 ms 3156 KB Output is correct
7 Correct 3 ms 3080 KB Output is correct
8 Correct 2 ms 3076 KB Output is correct
9 Correct 4 ms 3180 KB Output is correct
10 Correct 3 ms 3156 KB Output is correct
11 Correct 3 ms 3156 KB Output is correct
12 Correct 3 ms 3156 KB Output is correct
13 Correct 3 ms 3156 KB Output is correct
14 Correct 3 ms 3080 KB Output is correct

Subtask #3
23.0 / 23.0

# Verdict Execution time Memory Grader output
1 Correct 150 ms 45160 KB Output is correct
2 Correct 177 ms 48952 KB Output is correct
3 Correct 193 ms 49128 KB Output is correct
4 Correct 239 ms 51000 KB Output is correct
5 Correct 183 ms 51148 KB Output is correct
6 Correct 282 ms 53312 KB Output is correct

Subtask #4
41.0 / 41.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2772 KB Output is correct
2 Correct 3 ms 2844 KB Output is correct
3 Correct 3 ms 2820 KB Output is correct
4 Correct 5 ms 2868 KB Output is correct
5 Correct 2 ms 3156 KB Output is correct
6 Correct 3 ms 3156 KB Output is correct
7 Correct 3 ms 3080 KB Output is correct
8 Correct 2 ms 3076 KB Output is correct
9 Correct 4 ms 3180 KB Output is correct
10 Correct 3 ms 3156 KB Output is correct
11 Correct 3 ms 3156 KB Output is correct
12 Correct 3 ms 3156 KB Output is correct
13 Correct 3 ms 3156 KB Output is correct
14 Correct 3 ms 3080 KB Output is correct
15 Correct 150 ms 45160 KB Output is correct
16 Correct 177 ms 48952 KB Output is correct
17 Correct 193 ms 49128 KB Output is correct
18 Correct 239 ms 51000 KB Output is correct
19 Correct 183 ms 51148 KB Output is correct
20 Correct 282 ms 53312 KB Output is correct
21 Correct 128 ms 47872 KB Output is correct
22 Correct 154 ms 47736 KB Output is correct
23 Correct 186 ms 47848 KB Output is correct
24 Correct 222 ms 49948 KB Output is correct
25 Correct 233 ms 52952 KB Output is correct
26 Correct 149 ms 48148 KB Output is correct
27 Correct 164 ms 47832 KB Output is correct
28 Correct 187 ms 48184 KB Output is correct
29 Correct 252 ms 49680 KB Output is correct
30 Correct 252 ms 51244 KB Output is correct
31 Correct 152 ms 48640 KB Output is correct
32 Correct 163 ms 48464 KB Output is correct
33 Correct 193 ms 48736 KB Output is correct
34 Correct 208 ms 50724 KB Output is correct
35 Correct 253 ms 53668 KB Output is correct
36 Correct 192 ms 50560 KB Output is correct