從物理學到計算機,再到硬件,再到人工智能!
藍橋杯備賽 (LintCode上刷的第四題)
問題描述
Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.
樣例輸出
問題分析
這道題太簡單了,純粹是爲了記錄我的學習,才寫這篇博客的。當然我的代碼還有待改進!
JAVA實現代碼
package DP;
public class RangeSumQuery943_1111 {
/**
*
* @param arr
* @param low
* @param high
* @return
*/
public static int rangeSum(int[] arr, int low, int high) {
// 創建一個數組,保存從low下標開始相加的和,dp[j] 表示從第i位相加到j位的和
int[] dp = new int[arr.length + 1];
//dp數組賦初值
for (int i = 0; i < dp.length; i++) {
dp[i] = 0;
}
//計算low到high範圍的累加和
for (int i = low; i < high + 1; i++) {
dp[i + 1] = dp[i] + arr[i];
// System.out.println(dp[i]);
}
return dp[high + 1];
}
public static void main(String[] args) {
int[] nums = {-2, 0, 3, -5, 2, -1};
int result = rangeSum(nums, 0, 5);
System.out.println(result);
}
}