Why does signed integer overflow: 2147483647 throw:

runtime error: signed integer overflow: 2147483647 - -100 cannot be represented in type 'int' on this code

 temp = abs(nums[i] nums[j] nums[k]-target);

 if(temp < abs(minTarget-target)){
     minTarget = nums[i] nums[j] nums[k];
 }

?

CodePudding user response：

minTarget=nums[i] nums[j] nums[k];

nums[i], nums[j], nums[k] maybe below that maximum, but sum is above it.

CodePudding user response：

- -100 cannot be represented in type int

- -100 is 100 and can be represented as an int. It is the sum that is a problem.

2147483647 - -100 is mathematically 2147483747, yet that sum is outside OP's 32-bit int range of [-2147483648 ... 2147483647], hence the run-time error.

Code could use 64-bit math to forestall overflow. Yet the problem may remain if minTarget must remain int.

 long long temp = llabs(0LL   nums[i]   nums[j]   nums[k] - target);

 if(temp < llabs(0LL   minTarget - target)){
   minTarget = 0LL   nums[i]   nums[j]   nums[k];
 }

0LL ... insures at least 64-bit math in the addition/subtraction.