Submission #386676

#	Time	Username	Problem	Language	Result	Execution time	Memory
386676		ShivanshJ	A Huge Tower (CEOI10_tower)	C++17	30 / 100	152 ms	16108 KiB

tower

#include <bits/stdc++.h>
#define pb push_back
#define ll long long
#define int long long
using namespace std;
const ll MOD =  1e9 + 7;

ll powerm(ll a,ll b,ll m) { //m-> mod
    if(b==0) {
        return 1;
    }
    ll res=powerm(a,b/2,m);
    if(b%2) {
        return ((res*res)%m*(a%m))%m;
    }
    return (res*res)%m;
}

//INVERSE -> a^(m-2) ...m -> prime

ll power(ll a,ll b) {
    if(b==0) {
        return 1;
    }
    ll res=power(a,b/2);
    if(b%2==0) {
        return res*res;
    }
    return res*res*a;
}


/*void facm(ll m) { //factorial mod precompute
    fac[0]=1;
    for(int i=1;i<fac.size();i++) { //name an array fac
        fac[i]=((i)%m*fac[i-1])%m;
    }
    return;
}

ll choose(ll a,ll b,ll m) { //a choose b mod m
    ll ans=((fac[a]*(powerm(fac[a-b],m-2,m)))%m*powerm(fac[b],m-2,m))%m;
    return ans;
}*/


signed main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    //freopen("revegetate.in","r",stdin);
    //freopen("revegetate.out","w",stdout);
    int n,d;
    cin>>n>>d;
    vector<int>vec(n+1),t(n+1);
    vec[0]=0,t[0]=0,t[1]=1;
    for(int i=1;i<=n;i++) {
        cin>>vec[i];
    }
    sort(vec.begin(),vec.end());
    for(int i=2;i<=n;i++) {
        int first=1,last=i,j;
        while(first<=last) {
            int mid=(first+last)/2;
            if(vec[mid]>=vec[i]-d) {
                j=mid;
                last=mid-1;
            } else {
                first=mid+1;
            }
        }
        t[i]=(t[i-1]*(i-j+1))%MOD;
    }
    cout<<t[n];
    return 0;

}

Compilation message (stderr)

tower.cpp: In function 'int main()':
tower.cpp:71:24: warning: 'j' may be used uninitialized in this function [-Wmaybe-uninitialized]
   71 |         t[i]=(t[i-1]*(i-j+1))%MOD;
      |                       ~^~

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