제출 #1000940

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1000940		toilanvd	Salesman (IOI09_salesman)	C++14	0 / 100	532 ms	65536 KiB

salesman

#include <cstdio>
#include <algorithm>
#include <vector>
#include <iostream>
#define x first
#define y second

using namespace std;

typedef long long ll;
typedef pair<ll,ll> ii;

const ll INF= 1000000000000005LL, cons= 500001;

ll n, upcost, downcost, sta;
vector<ii> a[500005];
ll g[500005][2], f[500005][2], s[500005];
ll d[2][2000505];

void update(ll type, ll k, ll p, ll q, ll x, ll z){
    if(p>q || p>x || q<x) return;
    if(p==x && x==q){
        d[type][k]= z;
        return;
    }
    update(type,2*k,p,(p+q)/2,x,z);
    update(type,2*k+1,(p+q)/2+1,q,x,z);
    d[type][k]= max(d[type][2*k], d[type][2*k+1]);
}

ll get(ll type, ll k, ll p, ll q, ll x, ll y){
    if(p>q || p>y || q<x) return -INF;
    if(x<=p && q<=y) return d[type][k];
    return max(get(type,2*k,p,(p+q)/2,x,y),get(type,2*k+1,(p+q)/2+1,q,x,y));
}

int main(){
    //freopen("salesman.018.in","r",stdin);
    //freopen("salesman.out","w",stdout);
    ios_base::sync_with_stdio(false);
    cin >> n >> upcost >> downcost >> sta;
    a[0].push_back(ii(sta,0)); a[cons].push_back(ii(sta,0));
    for(ll i=1;i<=n;i++){
        ll x, y, z; cin >> x >> y >> z;
        a[x].push_back(ii(y,z));
    }
    for(ll i=1;i<=5*cons;i++){d[0][i]= -INF; d[1][i]= -INF;}
    update(0,1,1,cons,sta,upcost*sta);
    update(1,1,1,cons,sta,-downcost*sta);
    for(ll i=cons-1;i>=0;i--){
        if(a[i].empty()) continue;
        sort(a[i].begin(),a[i].end());
        ll maxi= -INF;
        for(ll j=0;j<(ll)a[i].size();j++){
            s[j+1]= s[j]+a[i][j].y;
            maxi= max(maxi, -s[j]+(upcost+downcost)*a[i][j].x);
            g[j+1][0]= maxi+(s[j+1]-(upcost+downcost)*a[i][j].x);
        }
        maxi= -INF;
        for(ll j=(ll)a[i].size()-1;j>=0;j--){
            maxi= max(maxi, s[j+1]-(upcost+downcost)*a[i][j].x);
            g[j+1][1]= maxi+(-s[j]+(upcost+downcost)*a[i][j].x);
        }
        for(ll j=0;j<(ll)a[i].size();j++){
            f[j+1][1]= get(0,1,1,cons,1,a[i][j].x)-upcost*a[i][j].x;
            f[j+1][1]= max(f[j+1][1], get(1,1,1,cons,a[i][j].x,cons)+downcost*a[i][j].x);
        }
        maxi= -INF;
        for(ll j=0;j<(ll)a[i].size();j++){
            maxi= max(maxi, f[j+1][1]+upcost*a[i][j].x-s[j]);
            f[j+1][0]= maxi+(-upcost*a[i][j].x+s[j]+g[j+1][1]);
        }
        maxi= -INF;
        for(ll j=(ll)a[i].size()-1;j>=0;j--){
            maxi= max(maxi, f[j+1][1]-downcost*a[i][j].x+s[j+1]);
            f[j+1][0]= max(f[j+1][0], maxi+(downcost*a[i][j].x-s[j+1]+g[j+1][0]));
        }
        for(ll j=0;j<(ll)a[i].size();j++){
            update(0,1,1,cons,a[i][j].x,f[j+1][0]+upcost*a[i][j].x);
            update(1,1,1,cons,a[i][j].x,f[j+1][0]-downcost*a[i][j].x);
        }
    }
    cout << f[1][0] << "\n";
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

salesman.cpp: In function 'int main()':
salesman.cpp:47:38: warning: iteration 2000504 invokes undefined behavior [-Waggressive-loop-optimizations]
   47 |     for(ll i=1;i<=5*cons;i++){d[0][i]= -INF; d[1][i]= -INF;}
      |                               ~~~~~~~^~~~~~
salesman.cpp:47:17: note: within this loop
   47 |     for(ll i=1;i<=5*cons;i++){d[0][i]= -INF; d[1][i]= -INF;}
      |                ~^~~~~~~~

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