C++ 代码描述

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
#include<iostream>

using namespace std;

int checkFalseCoin(int begin,int end,int coins[]){
  if((end-begin)==1){
    return (coins[end]>coins[begin])?end:begin;
  }
  if((( end - begin + 1 ) & 1) == 0 ){
    // 元素个数是双数
    int leftSum = 0,rightSum = 0;
    int middle = (end + begin + 1) / 2;
    for(int i = begin ; i < middle ; i ++ ){
      leftSum += coins[i];
    }
    for(int i = middle ; i <= end ; i ++ ){
      rightSum += coins[i];
    }
    if( leftSum < rightSum){
      return checkFalseCoin(middle,end,coins);
    }else if(leftSum > rightSum){
      return checkFalseCoin(begin,middle-1,coins);
    }else{
      return end;
    }
  }else{
    // 元素个数是单数
    int leftSum = 0,rightSum = 0;
    int middle = (end + begin) / 2;
    for(int i = begin ; i < middle ; i ++ ){
      leftSum += coins[i];
    }
    for(int i = middle + 1 ; i <= end ; i ++ ){
      rightSum += coins[i];
    }
    if( leftSum < rightSum){
      return checkFalseCoin(middle,end,coins);
    }else if(leftSum > rightSum){
      return checkFalseCoin(begin,middle,coins);
    }else{
      return middle;
    }
  }
}

int main(){
  int data[] = {1,1,1,1,1,2,1,1,1,1,1,1,1,1};
  int n = 14;
  std::cout << checkFalseCoin(0,n-1,data) << endl;
  return 0;
}