Submission #760472

#	Time	Username	Problem	Language	Result	Execution time	Memory
760472		vjudge1	Election (BOI18_election)	C++17	28 / 100	3054 ms	1840 KiB

election

#include <bits/stdc++.h>
using namespace std;
#define vi vector<int>
#define vl vector<long long>
#define vii vector<pair<int,int>>
#define vll vector<pair<long long,long long>>
#define pb push_back
#define ll long long
#define ld long double
#define nl '\n'
#define boost ios::sync_with_stdio(false)
#define mp make_pair
#define se second
#define fi first
#define fore(i, y) for(ll i = 0; i < y; i++)
#define forr(i,x,y) for(int i = x;i<=y;i++)
#define forn(i,y,x) for(ll i = y; i >= x; i--)
#define all(v) v.begin(),v.end()
#define sz(v) v.size()
#define clr(v,k) memset(v,k,sizeof(v))
#define rall(v) v.rbegin() , v.rend()
#define pii pair<int,int>
#define pll pair<ll , ll>

const ll MOD = 1e9 + 7;
const ll INF = 1e18 + 1;

ll gcd(ll a , ll b) {return b ? gcd(b , a % b) : a ;} // greatest common divisor (PGCD)
ll lcm(ll a , ll b) {return a * (b / gcd(a , b));} // least common multiple (PPCM)

// HERE IS THE SOLUTION
int solve(vi &v)
{
    int m = sz(v);
    vector<bool> vis(m , 0);
    vi pref(m) , suff(m);
    pref[0] = v[0];
    if(pref[0]<0)vis[0] = 1 , pref[0] = 0;
    suff[m - 1] = v[m - 1];
    if(suff[m - 1] < 0)vis[m - 1] = 1 , suff[m - 1] = 0;
    forr(i , 1 , m - 1)
    {
        pref[i] = pref[i - 1] + v[i];
        if(pref[i] < 0)
        {
            pref[i] = pref[i - 1];
            vis[i] = 1;
        }
    }
    forn(i , m - 2 , 0)
    {
        suff[i] = suff[i+1] + v[i];
        if(suff[i] < 0 || vis[i])
        {
            suff[i] = suff[i + 1];
            vis[i] = 1;
        }
    }
    int ans = 0;
    fore(i , m)if(vis[i])ans++;
    return ans;
}
int main()
{
    cin.tie(0);
    cout.tie(0);
    boost;
    int n , q;
    cin>>n;
    vi v(n);
    fore(i , n)
    {
        char c;
        cin>>c;
        v[i] = (c == 'C' ? 1 : -1);
    }
    cin>>q;
    while(q--)
    {
        int l , r;
        cin>>l>>r;
        vi a;
        forr(i , l - 1 , r - 1)
        {
            a.pb(v[i]);
        }
        cout<<solve(a)<<nl;
    }
}

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