区域和检索 - 数组不可变
解法一:累加
package com.kaesar.leetcode;
public class LeetCode_303 {
public static void main(String[] args) {
// 测试用例
NumArray numArray = new NumArray(new int[]{-2, 0, 3, -5, 2, -1});
System.out.println(numArray.sumRange(0, 2)); // return 1 ((-2) + 0 + 3)
System.out.println(numArray.sumRange(2, 5)); // return -1 (3 + (-5) + 2 + (-1))
System.out.println(numArray.sumRange(0, 5)); // return -3 ((-2) + 0 + 3 + (-5) + 2 + (-1))
}
}
class NumArray {
private int[] nums;
public NumArray(int[] nums) {
this.nums = nums;
}
public int sumRange(int left, int right) {
int result = 0;
for (int i = left; i <= right; i++) {
result += nums[i];
}
return result;
}