Title
Given an integer array nums, find the sum of the elements between indices i and j (i ≤ j), inclusive.
Example:
Given nums = [-2, 0, 3, -5, 2, -1]
sumRange(0, 2) -> 1
sumRange(2, 5) -> -1
sumRange(0, 5) -> -3
Solution
DP解决，用数组保存以前的和
//cpp:
class NumArray {
public:
vector<int> v;
NumArray(vector<int> nums) {
v.resize(nums.size()+1);
v[0]=0;
for(int i=0;i<nums.size();i++){
v[i+1]=v[i]+nums[i];
}
}
int sumRange(int i, int j) {
return v[j+1]-v[i];
}
};
/**
* Your NumArray object will be instantiated and called as such:
* NumArray obj = new NumArray(nums);
* int param_1 = obj.sumRange(i,j);
*/