ABC 379(E-F)

ABC379

E

伪装高精的找规律题

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define int long long
#define pii pair<int, int>
#define mkp make_pair
using namespace std;
const int N = 3e5 + 5;
int pre[N], ans[N];
signed main()
{ios::sync_with_stdio(false);int n;cin >> n;string s;cin >> s;s = '1' + s;for (int i = 1; i <= n; i++){pre[i] = pre[i - 1] + i * (s[i] - '0');}int rem=0;for(int i=n;i>=1;i--){ans[i]=(rem+pre[i])%10;rem=(pre[i]+rem)/10;}if(rem!=0){cout<<rem;}for(int i=1;i<=n;i++)cout<<ans[i];cout<<endl;
}

F

单调栈二分或者单调栈树状数组

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int, int>
#define mkp make_pair
using namespace std;
const int N = 2e5 + 5;
int pre[N], ans[N],t[N],h[N];
vector<pii>vt[N];
#define lowbit(x) (x&(-x))
int que(int x){int res=0;while(x>0){res+=t[x];x-=lowbit(x);}return res;
}
void upd(int x,int k){while(x<N){t[x]+=k;x+=lowbit(x);}
}signed main()
{ios::sync_with_stdio(false);int n, q;cin >> n >> q;stack<int> sta;for (int i = 1; i <= n; i++){cin >> h[i];}for(int i=1;i<=q;i++){int l,r;cin>>l>>r;vt[l].push_back(mkp(r,i));}for(int i=n;i>=1;i--){for(auto j:vt[i]){ans[j.second]=que(n)-que(j.first);}   while(!sta.empty()&&h[sta.top()]<h[i])upd(sta.top(),-1),sta.pop();sta.push(i);upd(i,1);}for(int i=1;i<=q;i++)cout<<ans[i]<<endl;
}