Different output with brackets for if statement in TWO SUM proble

I am attaching here the link to the TWO SUM problem in leet code: https://leetcode.com/problems/two-sum/

int* twoSum(int* nums, int numsSize, int target, int* returnSize){
    *returnSize=2;
    int *arr=malloc(sizeof(int)*2);
    int i,j;
    for(i=0;i<numsSize-1;i++){
        for(j=i+1;j<numsSize;j++){
            printf("i= %d j=%d,ans=%d\n",nums[i],nums[j],nums[i]+nums[j]);
            if(nums[i]+nums[j]==target){
               arr[0]=i; arr[1]=j;
            }
        }
    }
    return arr;
}

In the if statement of the above code upon adding the curly braces produces the following outputoutput image

but if i removed the curly braces of if statement then i get a different output as shown bracket of if statement removed