C :

#include<stdio.h>
int main() {
	int j, a, t;
	int n = 0, s = 0, m, i, leap = 1;
 	for (j = 0; j < 12; j++) {
 		t = scanf("%d", &a);
 		if (t != EOF) {
 			n += 300 - a;
 			if (n < 0 && leap == 1) {
 				i = j + 1;
 				leap = 0;
 			}
 			m = n / 100;
 			n -= m * 100;
 			s += m * 100;
 			if (j == 11) {
 				if (leap == 1) {
 					printf("%d\n", n + (s * 6) / 5);
				}
 				else {
 					printf("-%d\n", i);
 				}
 				n = s = 0;
 				j = -1;
 				leap = 1;
 			}
 		}
 		else
 			break;
 	}
	return 0;
} 

C++ :

#include <iostream>
#include <cstdio>
using namespace std;
int main()
{
    //jinjin，津津手里有多少钱
    //cunkuan,津津在妈妈那存了多少钱
    //num用来读取每月的消费预算
    int jinjin,cunkuan,num;
    bool flag=false;//破产标识，默认没破产
    jinjin=0;
    cunkuan=0;
    for(int i=1;i<=12;i++)
    {
        jinjin=jinjin+300;//每月月初妈妈给300元
        cin>>num;//读入本月预算
        if(jinjin<num)
        {//如果手里的钱不够预算，宣布本月破产并退出循环
            cout<<'-'<<i<<endl;
            flag=true;//破产了
            break;
        }
        else
        {            
            jinjin=jinjin-num;//如果钱够用，挥霍吧
            cunkuan=cunkuan+100*(jinjin/100);//剩下的钱，整百的存到妈妈那
            // jinjin=jinjin%100;//存完还剩多少钱
            jinjin=jinjin-100*(jinjin/100);
        }        
    }
    if(flag != true)
    {//要是没破产，输出手里剩余的钱加上妈妈那边连本带利的存款
        jinjin=jinjin+cunkuan*1.2;
        cout<<jinjin<<endl;
    }
    return 0;
}

Pascal :

var i,n,k,x:longint;
begin
  for i:=1 to 12 do
  begin
    readln(n);
    k:=k+300-n;
    if k<0 then
    begin
      write(-i);
      exit;
    end;
    x:=x+k div 100*100;
    k:=k mod 100;
  end;
  write(k+x div 100 * 120);
end.