title: Policemen Catch Thieves
signature: class Solution {
  
      public int PolicemenCatchThieves(List<char> arr, int n, int k) {
test_code: using System;
  using System.Numerics;
  using System.Diagnostics;
  using System.Collections.Generic;
  using System.Linq;
  using System.Text;
  using System.Security.Cryptography;
  using System.Web.UI;
  using System.Web.Script.Serialization;
  
  // SOLUTION CODE
  // ============================================
  PLACEHOLDER_CODE_BODY
  
  // TESTING CODE 
  // ============================================
  namespace EvaluatePrediction {
      class TestRunner {
          public bool ValidateSolution(int actual, int expected){
              return new JavaScriptSerializer().Serialize(actual) == new JavaScriptSerializer().Serialize(expected);
          }
  
          public string driver(List<char> arr, int n, int k, int expected){
              try{
                PLACEHOLDER_CLS_NAME solution_cls = new PLACEHOLDER_CLS_NAME();
                int pred_result = solution_cls.PLACEHOLDER_FN_NAME(arr, n, k); 
                if (ValidateSolution(
                      pred_result,
                      expected)){
                  return "PASSED";
                }
                return "FAILED";
              } 
              catch (Exception exception_obj)
              {
                return exception_obj.GetType().FullName;
              }
          }
          static void Main(string[] args) {
              TestRunner runner = new TestRunner();
              String result;
              result = runner.driver(
                  new List<char>{'A', 'B', 'B', 'D', 'E', 'E', 'F', 'G', 'G', 'G', 'I', 'J', 'O', 'P', 'Q', 'Q', 'Q', 'Q', 'R', 'R', 'S', 'U', 'X', 'Y', 'Y', 'c', 'd', 'h', 'i', 'i', 'i', 'i', 'k', 'k', 'l', 'l', 'l', 'l', 'm', 'p', 'r', 'r', 's', 't', 't', 'u', 'x', 'z'}, 33, 45, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-0...{0}",
                  result)
              );result = runner.driver(
                  new List<char>{'7', '6', '0', '1', '0', '1'}, 3, 3, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-1...{0}",
                  result)
              );result = runner.driver(
                  new List<char>{'0', '0', '0', '0', '0', '0', '0', '0', '0', '1', '1', '1', '1', '1', '1', '1', '1', '1'}, 9, 10, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-2...{0}",
                  result)
              );result = runner.driver(
                  new List<char>{'y', 'k', 'S', 'i', 's', 'r', 'i', 'z', 'y', 'f', 'E', 'U', 'y', 'G', 'f', 'f', 's', 'v', 'v', 'D', 'v', 'V', 'S', 'D', 'K', 'S', 'f', 'V', 'g', 'I', 'J', 'p', 'j', 'k', 'R', 'n', 'm', 'O', 'L', 'X', 'y', 'U', 'y', 'k', 'w'}, 24, 44, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-3...{0}",
                  result)
              );result = runner.driver(
                  new List<char>{'1', '1', '5', '8', '8'}, 2, 2, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-4...{0}",
                  result)
              );result = runner.driver(
                  new List<char>{'0', '1', '0', '0', '1', '1', '1', '0', '0', '0', '1', '0', '1', '0', '1', '0', '0', '0', '0', '0', '1', '0', '0', '0', '0', '1', '1', '1', '0', '0', '0', '0', '0', '0'}, 23, 18, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-5...{0}",
                  result)
              );result = runner.driver(
                  new List<char>{'A', 'I', 'K', 'Q', 'Q', 'X', 'Z', 'f', 'g'}, 5, 8, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-6...{0}",
                  result)
              );result = runner.driver(
                  new List<char>{'7', '0', '6', '9', '7', '5', '1', '3', '9', '8', '0', '0', '1', '3', '9', '2', '5', '5', '2', '7', '9', '3', '3', '9', '3', '8', '5', '5', '0', '4', '6', '2', '7', '4', '0', '4', '6', '4', '2', '3'}, 35, 28, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-7...{0}",
                  result)
              );result = runner.driver(
                  new List<char>{'0', '0', '0', '1', '1', '1', '1', '1', '1', '1', '1'}, 8, 10, 
                  0
              );
              Console.WriteLine(string.Format(
                  "TEST-8...{0}",
                  result)
              );result = runner.driver(
                  new List<char>{'D', 'C', 'P', 'H', 'G', 'o', 'u', 'P', 'T', 'G', 'E', 'U', 'n', 'E', 'U'}, 11, 12, 
                  1
              );
              Console.WriteLine(string.Format(
                  "TEST-9...{0}",
                  result)
              );
          }
      }
  }
  
source_py: def policemen_catch_thieves(arr, n, k):
      i = 0
      l = 0
      r = 0
      res = 0
      thi = []
      pol = []
      while (i < n):
          if (arr[i] == 'P'):
              pol.append(i)
          elif (arr[i] == 'T'):
              thi.append(i)
          i += 1
      while ((l < len(thi)) and (r < len(pol))):
          if (abs((thi[l] - pol[r])) <= k):
              res += 1
              l += 1
              r += 1
          elif (thi[l] < pol[r]):
              l += 1
          else:
              r += 1
      return res
source_cpp: int policemen_catch_thieves(vector<char> arr, int n, int k) {
    int res = 0;
    vector < int > thi;
    vector < int > pol;
    for ( int i = 0;
    i < n;
    i ++ ) {
      if ( arr [ i ] == 'P' ) pol . push_back ( i );
      else if ( arr [ i ] == 'T' ) thi . push_back ( i );
    }
    int l = 0, r = 0;
    while ( l < thi . size ( ) && r < pol . size ( ) ) {
      if ( abs ( thi [ l ] - pol [ r ] ) <= k ) {
        res ++;
        l ++;
        r ++;
      }
      else if ( thi [ l ] < pol [ r ] ) l ++;
      else r ++;
    }
    return res;
  }