제출 #570847

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
570847		amukkalir	Islands (IOI08_islands)	C++17	54 / 100	417 ms	131072 KiB

islands

#include "bits/stdc++.h"
using namespace std; 
 
#define pii pair<int, int> 
#define fi first 
#define se second 
#define pb push_back
 
const int nax = 1e6; 
int n; 
int p[nax+5]; 
bool vis[nax+5]; 
long long c[nax+5]; 
long long val[nax+5]; 
long long psum[nax+5]; 
vector<pii> adj[nax+5]; 
vector<int> cyc[nax+5]; 
vector<pii> edg; 
 
void gp(int u, int par, int ls=0) {
    p[u] = par; 
    for(pii t : adj[u]) {
        int v = t.fi; 
        int e = t.se; 
        if(e == ls) continue; 
 
        if(p[v] == 0) {
            gp(v, par, e); 
        } else {
            cyc[par].push_back(e); 
        }
    }
}
 
bool fc(int u, int go, int ls) {
    if(u == go) return true; 
 
    for(pii t : adj[u]) {
        int v = t.fi; 
        int e = t.se; 
        if(e == ls) continue; 
        
        bool ok = fc(v, go, e); 
        if(ok) {
            vis[u] = true; 
            vis[v] = true; 
            if(edg[e].fi != u) swap(edg[e].fi, edg[e].se); 
            cyc[p[go]].push_back(e); 
            return true; 
        } 
    }
 
    return false; 
}
 
long long trav(int u) {
    if(val[u]) return val[u]; 
 
    vis[u] = true; 
    long long res = 0; 
    for(pii t : adj[u]) {
        int v = t.fi; 
        int e = t.se; 
        if(!vis[v]) {
            res = max(res, c[e] + trav(v)); 
        }
    }
 
    return val[u] = res; 
}
 
long long sum (int l, int r, int i) {
    if(r < l) return psum[r] + psum[cyc[i].size()-1] - psum[l-1]; 
    if(l) return psum[r] - psum[l-1]; 
    return psum[r]; 
}
 
int main () {
    scanf("%d", &n); 
 
    edg.pb({0,0}); 
    for(int i=1; i<=n; i++) {
        long long l, j;         
        scanf("%lld %lld", &j, &l); 
 
        c[i] = l; 
        adj[j].pb({i,i}); 
        adj[i].pb({j,i}); 
        edg.pb({i,j}); 
    }
 
    long long ans = 0; 
    for(int i=1; i<=n; i++) {
        if(p[i] == 0) {
            gp(i,i); 
            cyc[i].pop_back(); 
            fc(edg[cyc[i][0]].se, edg[cyc[i][0]].fi, cyc[i][0]); 
 
            long long opt = 0; 
 
            priority_queue<long long> pq; 
            long long dpq = 0; 
            long long sum = 0; 
            int sz = cyc[i].size(); 
 
            for(int j=0; j<sz; j++) {
                int e = cyc[i][j]; 
                swap(edg[e].fi, edg[e].se); 
                sum += c[e]; 
                if(j+1 < sz) pq.push(sum + trav(edg[e].se)); 
            }
 
            for(int j=0; j<sz; j++) {
                int e = cyc[i][j]; 
                int u = edg[e].fi; 
                opt = max(opt, trav(u) + pq.top() + dpq); 
                dpq -= c[e]; 
                pq.push(trav(u) + sum - c[e] - dpq); 
            }
 
            ans += opt; 
        }
    }
 
    printf("%lld", ans); 
}

컴파일 시 표준 에러 (stderr) 메시지

islands.cpp: In function 'int main()':
islands.cpp:79:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   79 |     scanf("%d", &n);
      |     ~~~~~^~~~~~~~~~
islands.cpp:84:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   84 |         scanf("%lld %lld", &j, &l);
      |         ~~~~~^~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 27 / 33
• Subtask 2: 3 / 3
• Subtask 3: 4 / 4
• Subtask 4: 0 / 10
• Subtask 5: 10 / 10
• Subtask 6: 10 / 10
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 10