你应该先扣除每月的预计花销，然后再判断当月的钱是否不够用，余额是否大于100，之后存钱。
用python的话大概是这样，看懂应该没啥问题
```python
save,mum_save = 0,0
for i in range(12):
# 手中得到 300
save += 300
pay = int(input())
# 扣除每月预计花销
save -= pay
# 当月余额不足，程序结束
if (save<0):
print("-{}".format(i+1))
exit()
# 预计余额超过 100，存钱
if save >= 100:
mum_save += save // 100
save %= 100
save += mum_save * 120
print(save)
```
by Winds_Land @ 2024-01-27 11:43:42
如果没有取整输出就只有40
------------
```c
#include<stdio.h>
int main()
{
double in_for=0;
int out_inform[12];
int cun=0,now_m=0,moth,a;
for( a=0;a<12;a++)
{
scanf("%d",&out_inform[a]);
}
for( moth=0;moth<12;moth++)
{
now_m+=300;
now_m-=out_inform[moth];
if(now_m<0)
{
printf("-%d",moth+1);
return 0;
}
if(now_m>=100)
{
in_for+=((now_m/100)*100);
now_m%=100;
}
}
in_for*=1.2;
printf("%.0lf",in_for+now_m);
}
```
by DingZHen520 @ 2024-02-07 09:12:25
@[CHkuakeU](/user/1239495) printf(,0)
我加上.0就过了
by DingZHen520 @ 2024-02-07 09:13:19
@[DingZHen520](/user/1209614) 栓Q
by CHkuakeU @ 2024-02-21 15:00:46