303.md

#303. Range Sum Query - Immutable 题目链接

public class NumArray {

    private int[] nums;
    public NumArray(int[] nums) {
        // 预处理
        for (int i=1; i < nums.length; i++) {
            nums[i] += nums[i - 1];
        }
        this.nums = nums;
    }

    public int sumRange(int i, int j) {
        if (i == 0) {
            return nums[j];
        }
        return nums[j] - nums[i - 1];
    }
}