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NumArray.java
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NumArray.java
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package g0301_0400.s0303_range_sum_query_immutable;
// #Easy #Array #Design #Prefix_Sum #Programming_Skills_I_Day_12_Class_and_Object
// #2022_07_07_Time_7_ms_(100.00%)_Space_44.9_MB_(96.34%)
public class NumArray {
private int[] sums;
public NumArray(int[] nums) {
sums = new int[nums.length];
for (int i = 0; i < nums.length; i++) {
if (i == 0) {
sums[i] = nums[i];
} else {
sums[i] = sums[i - 1] + nums[i];
}
}
}
public int sumRange(int i, int j) {
if (i == 0) {
return sums[j];
}
return sums[j] - sums[i - 1];
}
}
/*
* Your NumArray object will be instantiated and called as such:
* NumArray obj = new NumArray(nums);
* int param_1 = obj.sumRange(left,right);
*/