Given an integer array nums, find the sum of the elements in the range from index i to j (i ≤ j), including two points i and j.
Implement the NumArray class:
NumArray(int[] nums) uses the array nums to initialize the object
int sumRange(int i, int j) returns the sum of the elements in the array nums from index i to j (i ≤ j), including two points i and j (that is, sum (nums[i], nums[i + 1],…, nums[j]))
Example:
Input:
["NumArray", "sumRange", "sumRange", "sumRange"]
[[[-2, 0, 3, -5, 2, -1]], [0, 2], [2, 5] , [0, 5]]
Output:
[null, 1, -1, -3]
解释：
NumArray numArray = new NumArray([-2, 0, 3, -5, 2, -1]);
numArray.sumRange(0, 2); // return 1 ((-2) + 0 + 3)
numArray.sumRange(2, 5); // return -1 (3 + (-5) + 2 + (-1))
numArray.sumRange(0, 5); // return -3 ((-2) + 0 + 3 + (-5) + 2 + (-1))
prompt:
0 <= nums.length <= 104
-105 <= nums[i] <= 105
0 <= i <= j < nums.length
最多调用 104 次 sumRange 方法
public class NumArray {
private static int[] nums=null;
public static void main(String[] args) {
int[] nums= {
-2, 0, 3, -5, 2, -1};
NumArray numArray = new NumArray(nums);
numArray.sumRange(0, 2);
numArray.sumRange(2, 5);
numArray.sumRange(0, 5);
}
public NumArray(int[] nums) {
this.nums=nums;
}
public int sumRange(int i, int j) {
int sum=0;
for(int k=i;k<=j;k++) {
sum+=this.nums[k];
}
return sum;
}
}