Submission #47258

#	Time	Username	Problem	Language	Result	Execution time	Memory
47258		ngkan146	Boat (APIO16_boat)	C++11	9 / 100	66 ms	4844 KiB

boat

#include <bits/stdc++.h>
#define ll long long
using namespace std;
const ll mod = (ll) 1e9+7;
int n, a[505], b[505];
ll f[505][3005];
ll g[505];

int main(){
    iostream::sync_with_stdio(0);
    cin >> n;
    vector <int> lst;
    for(int i=1;i<=n;i++)
        cin >> a[i] >> b[i],
        lst.push_back(a[i]),
        lst.push_back(b[i]);
    sort(lst.begin(), lst.end());
    lst.resize(unique(lst.begin(),lst.end()) - lst.begin());
    vector <pair<int,int> > range;
    for(int i=0;i<lst.size();i++){
        range.push_back({lst[i], lst[i]});
        if (i != lst.size() - 1 && lst[i]+1 <= lst[i+1]-1)
            range.push_back({lst[i]+1, lst[i+1]-1});
    }
    range.insert(range.begin(), {-1,-1});
    g[0] = 1;
    ll ans = 0;
    for(int j = 1;j < range.size();j ++){
        // f[i][j] = cnt of way that end at i and value of i in range j
        int len = range[j].second - range[j].first + 1;
        ll arr[505], sumG[505];
        arr[0] = 1;
        sumG[0] = g[0];
        for(int i=1;i<=n;i++)
            sumG[i] = (sumG[i-1] + g[i]) % mod,
            arr[i] = arr[i-1] * (len+1-i) % mod;

        for(int i=1;i<=n;i++){
            if (range[j].first < a[i] || b[i] < range[j].second)
                continue;
            int possiBoat = 0;
            ll tmp = 0;

            for(int ii=i;ii>=1;ii--){
                if (!(a[ii] <= range[j].first && range[j].second <= b[ii]))  continue;
                possiBoat += (a[ii] <= range[j].first && range[j].second <= b[ii]);
                tmp = (tmp + arr[possiBoat]) % mod;
                if (possiBoat > len)    break;
                f[i][j] = (f[i][j] + sumG[ii-1 ] * tmp % mod) % mod;
            }
            ans = (ans + f[i][j]) % mod;
        }
        for(int i=0;i<=n;i++){
            g[i] = (g[i] + f[i][j]) % mod;
        }
    }
    cout << ans;
}

Compilation message (stderr)

boat.cpp: In function 'int main()':
boat.cpp:20:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<lst.size();i++){
                 ~^~~~~~~~~~~
boat.cpp:22:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if (i != lst.size() - 1 && lst[i]+1 <= lst[i+1]-1)
             ~~^~~~~~~~~~~~~~~~~
boat.cpp:28:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int j = 1;j < range.size();j ++){
                   ~~^~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 0 / 22
• Subtask 3: 0 / 27
• Subtask 4: 0 / 42