Submission #759741

#	Time	Username	Problem	Language	Result	Execution time	Memory
759741		MarwenElarbi	Election (BOI18_election)	C++14	0 / 100	3 ms	340 KiB

election

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#define vi vector<int>
#define ve vector
#define ll long long
#define vl vector<ll>
#define vll vector<pair<ll,ll>>
#define onbit __builtin_popcount
#define ii pair<int,int>
#define vvi vector<vi>
#define vii vector<ii>
#define gii greater<ii>
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define INF 1e18
#define eps 1e-7
#define eps1 1e-2
#define optimise ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
#define MAX_A 1e5+5
using namespace std;
using namespace __gnu_pbds;
template <class T>
using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const ll MOD = 1e9+9;
const int nax = 2e3+5;
const int MAX_VAL = 1e6;
double PI=3.14159265359;
int arx[8]={1,1,0,-1,-1,-1, 0, 1};
int ary[8]={0,1,1, 1, 0,-1,-1,-1};
void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}
int n;
string t;
bool vis[nax];
int main(){
    optimise;
    /*#ifndef ONLINE_JUDGE
        freopen("input.txt", "r", stdin);
        freopen("output.txt", "w", stdout);
    #endif*/
    //setIO("redistricting");
    cin>>n;
    cin>>t;
    int q;cin>>q;
    vi pre(n,0);
    vi suf(n,0);
    for (int i = 0; i < n; ++i)
    {
        if (t[i]=='T') pre[i]++;
        if (i) pre[i]+=pre[i-1];
    }
    for (int i = n-1; i >= 0; --i)
    {
        if (t[i]=='T') suf[i]++;
        if (i<n-1) suf[i]+=suf[i+1];
    }
    while(q--)
    {
        int x,y;
        cin>>x>>y;
        x--;y--;
        int mx=0;
        int l=-1;
        int r=n;
        int ans;
        if (x==0){
            ans=0;
        }else ans=pre[x-1];
        while(r-l>1)
        {
            int mid=(r+l)/2;
            if(pre[mid]>ans)r=mid;
            else l=mid;
        }
        if (r>y){
            cout << 0<<endl;
            continue;
        }
        int cur=r;
        int ans1;
        if (y==n-1) ans1=0;
        else ans1=suf[y+1];
        l=-1;r=n;
        while(r-l>1){
            int mid=(r+l)/2;
            if (suf[mid]>ans) l=mid;
            else r=mid;
        }
        int cur1=l;
        //cout << cur<<" "<<cur1<<endl;
        //cout << suf[cur]<<" "<<pre[cur1]<<endl;
        //cout << ans1<<" "<<ans<<endl;
        cout <<max((suf[cur]-ans1-(y-cur+1-suf[cur]+ans1)),pre[cur1]-ans-(cur1-x+1-pre[cur1]+ans))<<endl;
    }

}

Compilation message (stderr)

election.cpp: In function 'int main()':
election.cpp:66:13: warning: unused variable 'mx' [-Wunused-variable]
   66 |         int mx=0;
      |             ^~
election.cpp: In function 'void setIO(std::string)':
election.cpp:33:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:34:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 28
• Subtask 2: 0 / 54
• Subtask 3: 0 / 18