给定 nums = [-2, 0, 3, -5, 2, -1],求和函数为 sumRange()
sumRange(0, 2) -> 1
sumRange(2, 5) -> -1
sumRange(0, 5) -> -3
package structures;
class NumArray {
private int[] sum;
public NumArray(int[] nums) {
if (nums.length > 0) {
sum = new int[nums.length + 1];
// 0表示一个元素也没有 2表示两个元素的和
sum[0] = 0;
for (int i = 1; i < nums.length; i++) {
sum[i] = sum[i - 1] + nums[i - 1];
}
}
}
public int sumRange(int i, int j) {
return sum[j + 1] - sum[i];
}
public static void main(String[] args) {
int[] nums = {-2, 0, 3, -5, 2, -1};
NumArray obj = new NumArray(nums);
int param_1 = obj.sumRange(1, 4);
System.out.println(param_1);
}
}
/**
* Your NumArray object will be instantiated and called as such:
* NumArray obj = new NumArray(nums);
* int param_1 = obj.sumRange(i,j);
*/
package structures;
class NumArray {
private int[] sum;
public NumArray(int[] nums) {
if (nums.length > 0) {
sum = new int[nums.length + 1];
// 0表示一个元素也没有 2表示两个元素的和
sum[0] = 0;
for (int i = 1; i < nums.length; i++) {
sum[i] = sum[i - 1] + nums[i - 1];
}
}
}
public int sumRange(int i, int j) {
return sum[j + 1] - sum[i];
}
public static void main(String[] args) {
int[] nums = {-2, 0, 3, -5, 2, -1};
NumArray obj = new NumArray(nums);
int param_1 = obj.sumRange(1, 4);
System.out.println(param_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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