Submission #569738

#	Time	Username	Problem	Language	Result	Execution time	Memory
569738		ryangohca	Swapping Cities (APIO20_swap)	C++17	30 / 100	1308 ms	33260 KiB

swap

#include "swap.h"

#include <bits/stdc++.h>
using namespace std;
int p[100001], pweight[100001][20], st[100001], en[100001], lineWeight[100001][20], twok[100001][20];
void init(int N){
    iota(p, p+N, 0);
    iota(st, st+N, 0);
    iota(en, en+N, 0);
    for (int i = 0; i < N; i++) lineWeight[i][0] = 2e9;
    memset(twok, -1, sizeof twok);
    memset(pweight, -1, sizeof pweight);
}
int fs(int x){
    if (p[x] == x) return x;
    return p[x] = fs(p[x]);
}
void ms(int x, int y, int w){
    int px = fs(x), py = fs(y);
    if (px == py){
        st[px] = en[px] = -1;
        lineWeight[px][0] = min(lineWeight[px][0], w);
        return;
    }
    p[py] = px; // px -> py
    //cout << px << ' ' << py << ' ' << w << endl;
    twok[py][0] = px;
    pweight[py][0] = w;
    if (st[px] != -1 && st[py] != -1){
        if ((st[px] == x || en[px] == x) && (st[py] == y || en[py] == y)){
            st[px] = (st[px] == x ? en[px] : st[px]);
            en[px] = (st[py] == y ? en[py] : st[py]);
        } else {
            st[px] = en[px] = -1;
            lineWeight[px][0] = min(lineWeight[px][0], w);
        }
    } else if (st[px] != -1){
        st[px] = en[px] = -1;
      	lineWeight[px][0] = w;
    } else {
        lineWeight[px][0] = min(lineWeight[px][0], lineWeight[py][0]);
    }
}
void init(int N, int M,
          std::vector<int> U, std::vector<int> V, std::vector<int> W) {
    init(N);
    vector<tuple<int, int, int>> edges;
    for (int i = 0; i < M; i++){
        edges.push_back({W[i], U[i], V[i]});
    }
    sort(edges.begin(), edges.end());
    for (auto [w, a, b] : edges){
        ms(a, b, w);
    }
    for (int i = 1; i <= 19; i++){
        for (int j = 0; j < N; j++){
            if (twok[j][i-1] != -1){
                twok[j][i] = twok[twok[j][i-1]][i-1];
                pweight[j][i] = max(pweight[j][i-1], pweight[twok[j][i-1]][i-1]);
                lineWeight[j][i] = min(lineWeight[j][i-1], lineWeight[twok[j][i-1]][i-1]);
            }
        }
    }
}
bool isOkay(int mid, int X, int Y){
    int w = 2e9;
    for (int i = 19; i >= 0; i--){
        if (twok[X][i] != -1 && pweight[X][i] <= mid) {w = min(w, lineWeight[X][i]); X = twok[X][i];}
        if (twok[Y][i] != -1 && pweight[Y][i] <= mid) {w = min(w, lineWeight[Y][i]); Y = twok[Y][i];}
    }
    if (X != Y) return false;
    //cout << mid << ' ' << min(lineWeight[X][0], w) << endl;
    return min(lineWeight[X][0], w) <= mid;
}
int getMinimumFuelCapacity(int X, int Y) {
    int mini = 0, maxi = 1e9+10;
    while (maxi - mini > 1){
        int mid = (maxi + mini) / 2;
        if (isOkay(mid, X, Y)) maxi = mid;
        else mini = mid;
    }
    return (maxi==1e9+10?-1:maxi);
}

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 17 / 17
• Subtask 4: 0 / 20
• Subtask 5: 0 / 23
• Subtask 6: 0 / 27