Submission #1020665

#	Time	Username	Problem	Language	Result	Execution time	Memory
1020665		fimh	Untitled (POI11_rot)	C++17	100 / 100	216 ms	16748 KiB

Main

#include <bits/stdc++.h>
//  #include "D:/debug.h"
using namespace std;
 
const int MAXN = 4e6 + 5;
 
// #define int long long

int n;
int g[MAXN][2];
int sz[MAXN];
long long dp[MAXN];
int a[MAXN];

struct fenwick_tree {
    int bit[MAXN + 5];
    void update(int pos, int v) {
        while(pos <= n) {
            bit[pos] += v;
            pos += (pos & (-pos));
        }
    }
    int get(int pos) {
        int ans = 0;
        while(pos) {
            ans += bit[pos];
            pos -= (pos & (-pos));
        }
        return ans;
    }
    int getR(int l, int r){
        return get(r) - get(l - 1);
    }
} ft;

int tdfs = 0, cnt = 0;

void build_tree(int u) {
    for(int i=0; i<2; i++) {
        int x;
        cin>>x;
        if(x == 0) {
            tdfs++;
            g[u][i] = tdfs;
            build_tree(tdfs);
        }
        else {
            tdfs++;
            g[u][i] = tdfs;
            a[tdfs] = x;
            cnt++;
        }
        if(cnt == n) return;
    }
}

void calsz(int u){
    sz[u] = 1;
    for(int i = 0; i < 2; i++){
        if(g[u][i] != 0) calsz(g[u][i]), sz[u] += sz[g[u][i]];
    }
}

void mod(int u, int val){
    if(a[u] != 0) ft.update(a[u], val);
    for(int i = 0; i < 2; i++)
        if(g[u][i] != 0) mod(g[u][i], val);
}

long long c1, c2;
void cal(int u){
    if(a[u] != 0){
        c1 += ft.get(a[u] - 1);
        c2 += ft.getR(a[u] + 1, n);
    }
    for(int i = 0; i < 2; i++)
        if(g[u][i] != 0) cal(g[u][i]);
}

void dfs(int u){
    int bc = 0;
    for(int i = 0; i < 2; i++){
        if(sz[g[u][i]] > sz[bc]) bc = g[u][i];
    }
    for(int i = 0; i < 2; i++)
        if(g[u][i] != bc && g[u][i] != 0) dfs(g[u][i]), dp[u] += dp[g[u][i]], mod(g[u][i], -1);
    
    if(bc) dfs(bc), dp[u] += dp[bc];

    if(a[u] != 0) ft.update(a[u], 1);
    c1 = 0, c2 = 0;
    for(int i = 0; i < 2; i++)
        if(g[u][i] != bc && g[u][i] != 0) cal(g[u][i]);
    
    dp[u] += min(c1,c2);

    for(int i = 0; i < 2; i++)
        if(g[u][i] != bc && g[u][i] != 0) mod(g[u][i], 1);
}
 
int main(){
    cin >> n;
    build_tree(0);
    calsz(1);
    dfs(1);
    cout << dp[1];
}

• Subtask 1: 9 / 9
• Subtask 2: 9 / 9
• Subtask 3: 9 / 9
• Subtask 4: 9 / 9
• Subtask 5: 9 / 9
• Subtask 6: 9 / 9
• Subtask 7: 9 / 9
• Subtask 8: 9 / 9
• Subtask 9: 9 / 9
• Subtask 10: 9 / 9
• Subtask 11: 10 / 10