这部分的重点是：将【A-Z，a-z，0-9】转换为ASCII值，可以进行巧妙的减法使其的范围在100以内。

char change(char c){
  if(c >= '0' && c <= '9')  return c - '0';  // 0-9
  else if(c >= 'A' && c <= 'Z') return c - 'A' + 10;  //10-35
  else if(c >= 'a' && c <= 'z') return c - 'a' + 36;  //36-61
}

满分代码

#include <iostream>
#include <bits/stdc++.h> 
using namespace std;
/* run this program using the console pauser or add your own getch, system("pause") or input loop */

char change(char c){
  if(c >= '0' && c <= '9')  return c - '0';
  else if(c >= 'A' && c <= 'Z') return c - 'A' + 10;
  else if(c >= 'a' && c <= 'z') return c - 'a' + 36;
}

int main(int argc, char** argv) {
  
  string s1, s2;
  int hashBread[100] = {0};
  
  int id = 0;
  cin >> s1 >> s2;
  
  int len1 = s1.length();
  int len2 = s2.length();
  
  char c1;
  for(int i = 0; i < len1; i++){
    c1 = change(s1[i]);
    hashBread[c1]++;
  }
  
  for(int i = 0; i < len2; i++){
    c1 = change(s2[i]);
    hashBread[c1]--;
  }
  
  bool isEnough = true; //true则为够用 
  
  int num = 0;
  
  for(int i = 0; i < 100; i++){
    if(hashBread[i] < 0){
      isEnough = false; 
      num+=(-hashBread[i]);
    }
  }
  
  if(isEnough == false){
    cout << "No " << num;
    return 0;
  }
  
  for(int i = 0; i < 100; i++){
    if(hashBread[i]!=0){
      num += hashBread[i];
    }
  }
  
  cout << "Yes " << num;
  
  return 0;
}