leetcode/code/lc303.java at master · mJackie/leetcode · GitHub

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package code;

* 303. Range Sum Query - Immutable

* 题意：i到j的和

* 难度：Easy

* 分类：Dynamic Programming

* 思路：

* Tips：Bingo!

* lc303, lc437, lc560

public class lc303 {

class NumArray {

int[] arr;

public NumArray(int[] nums) {

arr = nums;

for(int i=1; i<arr.length; i++){

arr[i] = arr[i-1]+arr[i];

}

public int sumRange(int i, int j) {

return i==0? arr[j] : arr[j]-arr[i-1];

}

/**

* Your NumArray object will be instantiated and called as such:

* NumArray obj = new NumArray(nums);

* int param_1 = obj.sumRange(i,j);

}

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