Submission #433618

#	Time	Username	Problem	Language	Result	Execution time	Memory
433618		LouayFarah	Election (BOI18_election)	C++14	0 / 100	248 ms	400 KiB

election

#include "bits/stdc++.h"
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)

typedef long long ll;
typedef string str;
typedef double db;
typedef long double ld;
typedef pair<int, int> pi;
#define fi first
#define se second

#define pb push_back
#define mp make_pair
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rall(x) rbegin(x), rend(x)
#define endl "\n"

#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)

const ll MOD = 1e9 + 7; //998244353
const ll INF = 1e18;
const ll MX = 1e9 + 10;
const int nx[4] = {0, 0, 1, -1}, ny[4] = {1, -1, 0, 0}; //right left down up

#ifndef LOCAL
#define cerr if(false) cerr
#endif
#define debug(x) cerr << #x << " : " << x << endl;
#define debugs(x,y) cerr << #x << " : " << x << " / " << #y << " : " << y << endl;
#define debugv(v) cerr << #v << " : " << "[ "; for(auto it : v) cerr << it << ' '; cerr << ']' << endl;
#define here() cerr << "here" << endl;

void IO() {
#ifdef LOCAL
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif
}

struct segtree
{
    int size;
    vector<ll> sums;

    void init(int n)
    {
        size = 1;
        while(size<n) size*=2;
        sums.assign(2*size, 1e9);
    }

    void set(int i, int v, int x, int lx, int rx)
    {
        if(rx-lx==1)
        {
            sums[x] = v;
            return;
        }

        int mid = (lx+rx)/2;

        if(i<mid)
            set(i, v, 2*x+1, lx, mid);
        else
            set(i, v, 2*x+2, mid, rx);

        sums[x] = min(sums[2*x+1], sums[2*x+2]);
    }

    void set(int i, int v)
    {
        set(i, v, 0, 0, size);
    }


    ll sum(int l, int r, int x, int lx, int rx)
    {
        if(lx>=r||l>=rx) return 1e9;
        if(lx>=l&&rx<=r) return sums[x];

        int mid = (lx+rx)/2;
        ll s1 = sum(l, r, 2*x+1, lx, mid);
        ll s2 = sum(l, r, 2*x+2, mid, rx);
        return min(s1, s2);
    }

    ll sum(int l, int r)
    {
        return sum(l, r, 0, 0, size);
    }
};

int main()
{
    boost;
    IO();

    ll n;
    cin >> n;

    string s;
    cin >> s;

    vector<ll> pre(n);
    if(s[0]=='C')
        pre[0] = 1;
    else
        pre[0] = -1;

    FOR(i, 1, n)
    {
        pre[i] = pre[i-1];
        if(s[i]=='C')
            pre[i]+=1;
        else
            pre[i]-=1;
    }

    vector<ll> suff(n);

    if(s[n-1]=='C')
        suff[n-1] = 1;
    else
        suff[n-1] = -1;

    for(int i = n-2; i>=0; i--)
    {
        suff[i]+=suff[i+1];
        if(s[i]=='C')
            suff[i] += 1;
        else
            suff[i]-=1;
    }

    segtree treepre, treesuff;
    treepre.init(n);
    FOR(i, 0, n)
        treepre.set(i, pre[i]);

    treesuff.init(n);
    FOR(i, 0, n)
        treesuff.set(i, suff[i]);

    ll q;
    cin >> q;
    while(q--)
    {
        ll l, r;
        cin >> l >> r;


        ll removesuff = 0, removepre = 0;
        if(r<=n-1)
            removesuff = suff[r];

        if(l-2>=0)
            removepre = pre[l-2];

        for(int i = l-1; i<r; i++)
            treepre.set(i, treepre.sums[i] - removepre);
        for(int i = l-1; i<r; i++)
            treesuff.set(i, treesuff.sums[i] -removesuff);

        ll min1 = treepre.sum(l-1, r-1);
        ll min2 = treesuff.sum(l-1, r-1);

        ll res = min(min1, min2);
        if(res<0)
            cout << -res << endl;
        else
            cout << 0 << endl;

        for(int i = l-1; i<r; i++)
            treepre.set(i, treepre.sums[i] +2*removepre);
        for(int i = l-1; i<r; i++)
            treesuff.set(i, treesuff.sums[i] +2*removesuff);
    }

    return 0;
}

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