303. Range Sum Query - Immutable

leet303.c

#include <stdio.h>
#include <stdlib.h>

struct NumArray {
	int *nums;
	int numsSize;
};

/** Initialize your data structure here. */
struct NumArray* NumArrayCreate(int* nums, int numsSize) {
    struct NumArray *numArray;
    int i;
	
    numArray = malloc (sizeof(struct NumArray) * 1);
    numArray->nums = malloc (sizeof(int) * numsSize);
    numArray->numsSize = numsSize;
    
    numArray->nums[0] = nums[0];
    for (i = 1; i < numsSize; i++) {
		numArray->nums[i] = numArray->nums[i-1] + nums[i];
    }

	return numArray;
}

int sumRange(struct NumArray* numArray, int i, int j) {
	int result = 0;
	
    if (i == 0)
        result = numArray->nums[j];
    else
        result = numArray->nums[j] - numArray->nums[i-1];
	
	return result;
}

/** Deallocates memory previously allocated for the data structure. */
void NumArrayFree(struct NumArray* numArray) {
    free(numArray->nums);
    numArray->numsSize = 0;
    numArray->nums = NULL;
}

int main() {
    int numsSize = 1;
    int *nums = malloc (sizeof(int) * numsSize);
    
    nums[0] = -1;
    
    struct NumArray* numArray = NumArrayCreate(nums, numsSize);
    int result = sumRange(numArray, 0, 0);
    
    NumArrayFree(numArray);
    
    printf("%d\n", result);

    return 0;
}