960A - Check the string - CodeForces Solution

#include <iostream>
#include <algorithm>
#include <math.h>
#include "string.h"
#include <vector>
#include <stack>
#include <queue>

using namespace std;

struct Node
{
    int val = 0;
    Node *le = nullptr;
    Node *ri = nullptr;
};

Node *head;

void setVal(Node **cur, int pos, int cle, int cri)
{
    //cout << "cle=" << cle << ", cri=" << cri << ", cur=" << cur << "\n";

    if ((*cur) == nullptr)
    {
        (*cur) = new Node;
    }

    if (cle == cri)
    {
        (*cur)->val = 1;
        return;
    }

    int m = (cle+cri)/2;

    if (pos <= m)
    {
        setVal(&((*cur)->le), pos, cle, m);
    }
    else
    {
        setVal(&((*cur)->ri), pos, m+1, cri);
    }

    ((*cur)->val)++;
}

int getAns(Node *cur, int le, int ri, int cle, int cri)
{
    if (cur == nullptr || le > ri)
    {
        return 0;
    }

    if (le == cle && ri == cri)
    {
        return cur->val;
    }

    int m = (cri+cle)/2;

    return getAns(cur->le, le, min(ri, m), cle, m) +
           getAns(cur->ri, max(le, m+1), ri, m+1, cri);
}

char op[3][4] = {"MOV", "ADD", "SUB"};
uint8_t r[4];
char cmd[100000];

void opReg(int rix, int st, int val)
{
    rix--;
    switch(st)
    {
    case 0:
        r[rix] = val;
        break;
    case 1:
        r[rix] += val;
        break;
    case 2:
        r[rix] -= val;
        break;
    }

    cout << "r" << rix + 1 << "=" << (int)r[rix] << "\n";
}

bool isRegOk(int ix, int le, int &rix)
{
    if (cmd[ix] < '1' || cmd[ix] > '4')
    {
        return false;
    }

    if (ix + 1 < le && (cmd[ix+1] == ' ' || cmd[ix+1] == ','))
    {
        rix = cmd[ix] - '0';
        return true;
    }

    if (ix + 1 >= le)
    {
        rix = cmd[ix] - '0';
        return true;
    }

    return false;
}

bool isDigit(char ch)
{
    return (ch >= '0' && ch <= '9');
}

bool isNum(int ix, int le, int &val)
{
    cerr << "isNum for " << cmd + ix << "\n";
    int res = 0;

    if (!isDigit(cmd[ix]))
    {
        return false;
    }

    res = cmd[ix] - '0';
    ix++;
    while (ix < le && isDigit(cmd[ix]))
    {
        res *= 10;
        res += cmd[ix] - '0';
        ix++;
    }

    //cout << "res=" << "\n";
    if ((ix < le && (cmd[ix] == ' ' || cmd[ix] == '\r')) || ix == le)
    {
        val = res;
        cout << "val=" << val << "\n";
        return true;
    }
    //cout << "bug\n";

    return false;
}

char s[5001];

void solve()
{
   int n;
   cin >> s;

   n = strlen(s);

   int c[2] = {0,0};
   int pos = 0;
   int cc =0;
   while (pos < n && s[pos] == 'a') {c[0]++; pos++;}
   while (pos < n && s[pos] == 'b') {c[1]++; pos++;}
   while (pos < n && s[pos] == 'c') {cc++; pos++;}

   if (pos < n || c[0] == 0 || c[1] == 0 || (c[0] != cc && c[1] != cc))
   {
       cout << "NO\n";
   }
   else
   {
       cout << "YES\n";
   }

   return;
}



void precalc()
{
}

int main()
{
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);

    int t = 1;
    //cin >> t;

    precalc();

    for (int i = 0; i < t; ++i)
    {
        solve();
    }
    return 0;
}