Submission #297115

#	Time	Username	Problem	Language	Result	Execution time	Memory
297115		Mercenary	Shortcut (IOI16_shortcut)	C++14	31 / 100	2047 ms	512 KiB

shortcut

#include "shortcut.h"
#include<bits/stdc++.h>
using namespace std;
const int maxn = 1e3 + 6;
typedef long long ll;

ll prv[maxn];
ll suf[maxn];
ll cur[maxn];
ll pre_res[maxn];
ll suf_res[maxn];

long long find_shortcut(int n, std::vector<int> l, std::vector<int> d, int c)
{
    vector<ll> sum(n , 0);
    for(int i = 1 ; i < n ; ++i){
        sum[i] = sum[i - 1] + l[i - 1];
    }
    auto dis = [&](int i , int j){
        return sum[j] - sum[i];
    };
    for(int i = 0 ; i < n ; ++i){
        if(i > 0)prv[i] = prv[i - 1] + l[i - 1];
        prv[i] = max(prv[i] , (ll)d[i]);
    }
    for(int i = n - 1 ; i >= 0 ; --i){
        if(i + 1 < n)suf[i] = suf[i + 1] + l[i];
        suf[i] = max(suf[i] , (ll)d[i]);
    }
    ll res = 0;
    for(int i = 0 ; i < n ; ++i){
        for(int j = i + 1 ; j < n ; ++j){
            res = max(res , dis(i , j) + d[i] + d[j]);
            pre_res[j] = max(pre_res[j] , dis(i , j) + d[i] + d[j]);
            suf_res[i] = max(suf_res[i] , dis(i , j) + d[i] + d[j]);
        }
    }
    for(int i = 1 ; i < n ; ++i)pre_res[i] = max(pre_res[i] , pre_res[i - 1]);
    for(int i = n - 2 ; i >= 0 ; --i)suf_res[i] = max(suf_res[i] , suf_res[i + 1]);
    for(int i = 0 ; i < n ; ++i){
        for(int j = i + 1 ; j < n ; ++j){
            cur[j] = d[j];
            if(dis(i,j) <= c)continue;
            ll mx = max(pre_res[i] , suf_res[j]);
            cur[i] = prv[i];
            cur[j] = suf[j];
            for(int k = i ; k <= j ; ++k){
                for(int t = k + 1 ; t <= j ; ++t){
                    mx = max(mx , cur[k] + cur[t] + min(dis(k, t) , dis(i,j) + c - dis(k,t)));
                    if(mx >= res)break;
                }
            }
            cur[j] = d[j];
            res = min(res , mx);
        }
    }
    return res;
}

#ifdef LOCAL
#include <cstdio>
#include <cassert>
#include "shortcut.h"

int main()
{
    freopen("A.INP","r",stdin);
    freopen("A.OUT","w",stdout);
    int n, c;
    assert(2 == scanf("%d%d", &n, &c));

    std::vector<int> l(n - 1);
    std::vector<int> d(n);
    for (int i = 0; i < n - 1; i++)
        assert(1 == scanf("%d", &l[i]));
    for (int i = 0; i < n; i++)
        assert(1 == scanf("%d", &d[i]));

    long long t = find_shortcut(n, l, d, c);


    printf("%lld\n", t);

    return 0;
}

#endif // LOCAL

• Subtask 1: 9 / 9
• Subtask 2: 14 / 14
• Subtask 3: 8 / 8
• Subtask 4: 0 / 7
• Subtask 5: 0 / 33
• Subtask 6: 0 / 22
• Subtask 7: 0 / 4
• Subtask 8: 0 / 3