PU Range Sum Query – Immutable

typedef struct {
    int *sums;
    int sumsSize; 
} NumArray;

NumArray* numArrayCreate(int* nums, int numsSize) {
    NumArray *res = malloc(sizeof(NumArray));
    res->sums = malloc((numsSize + 1) * sizeof(int));
    res->sumsSize = numsSize + 1;
    res->sums[0] = 0;
    int i;
    for (i = 0; i < numsSize; i++) {
        res->sums[i + 1] = nums[i] + res->sums[i]; 
    }
    return res;
}

int numArraySumRange(NumArray* obj, int i, int j) {
    return obj->sums[j + 1] - obj->sums[i];
}

void numArrayFree(NumArray* obj) {
    free(obj->sums);
    free(obj);
}

/**
 * Your NumArray struct will be instantiated and called as such:
 * struct NumArray* obj = numArrayCreate(nums, numsSize);
 * int param_1 = numArraySumRange(obj, i, j);
 * numArrayFree(obj);
 */