Submission #10405906

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Source Code Expand

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
using namespace std;
const int maxn = 110;
const int maxk = 100100;
const ll mod = 1e9 + 7;

ll n, k;
ll a[maxn];

ll dp[maxk];
ll pref[maxk];

int main() {
	cin>>n>>k;
	
	cin>>a[1];
	for(int i=0;i<=a[1];i++) {
		dp[i] = 1LL;
	}

	pref[0] = dp[0];
	for(int i=1;i<=k;i++) {
		pref[i] = pref[i-1] + dp[i];
	}
	for(int i=2;i<=n;i++) {
		cin>>a[i];

		memset(dp, 0, sizeof(dp));

		for(int j=k;j>=0;j--) {
			if(j - a[i] <= 0) {
				//cout<<j<<": "<<pref[j]<<"\n";
				dp[j] += pref[j];
				dp[j] %= mod;
			}
			else 
				dp[j] += pref[j] - pref[j-a[i]];
				dp[j] %= mod;
		}

		pref[0] = dp[0];
		for(int j=1;j<=k;j++) {
			pref[j] = pref[j-1] + dp[j];
			pref[j] %= mod;
		}
	}
	cout<<dp[k]<<"\n";
}

Submission Info

Judge Result