/
307.java
167 lines (140 loc) · 4.11 KB
/
307.java
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__________________________________________________________________________________________________
sample 51 ms submission
class NumArray {
//start segment tree
class SegmentTreeNode {
int start;
int end;
int sum;
SegmentTreeNode left;
SegmentTreeNode right;
public SegmentTreeNode( int start, int end) {
this.start=start;
this.end=end;
this.left=null;
this.right=null;
this.sum=0;
}
}
SegmentTreeNode root=null;
private SegmentTreeNode buildSegmentTree(int[] nums, int start, int end) {
if(start>end) return null;
SegmentTreeNode ret=new SegmentTreeNode(start, end);
if(start==end) {
ret.sum=nums[start];
}else {
int mid=start+(end-start)/2;
ret.left=buildSegmentTree(nums, start, mid);
ret.right=buildSegmentTree(nums, mid+1, end);
ret.sum=ret.left.sum+ret.right.sum;
}
return ret;
}
public void updateSegmentTree(SegmentTreeNode root, int pos, int val) {
if(root.start==root.end) {
root.sum=val;
return;
}
int mid=root.start+(root.end-root.start)/2;
if(pos<=mid)
updateSegmentTree(root.left, pos, val);
else
updateSegmentTree(root.right, pos, val);
root.sum=root.left.sum+root.right.sum;
}
public int sumRangeSegmentTree(SegmentTreeNode root, int start, int end) {
if(root.end==end && root.start==start)
return root.sum;
int mid=root.start+(root.end-root.start)/2;
if(end<=mid)
return sumRangeSegmentTree(root.left, start, end);
else if(start>=mid+1)
return sumRangeSegmentTree(root.right, start, end);
else
return sumRangeSegmentTree(root.left, start, mid) + sumRangeSegmentTree(root.right, mid+1, end);
}
//end segment tree
public NumArray(int[] nums) {
//root=buildSegmentTree(nums, 0, nums.length-1);
this.size=nums.length;
this.BITTree=new int[size+1];
this.nums=nums;
for(int i=0; i<size; i++) {
updateBITTree(i+1, nums[i]);
}
}
public void update(int i, int val) {
//updateSegmentTree(root, i, val) ;
updateBITTree(i+1, val-nums[i]);
nums[i]=val;
}
public int sumRange(int i, int j) {
//return sumRangeSegmentTree(root, i, j);
return getSum(j+1)-getSum(i);
}
//start BIT binary index tree
int[] BITTree;
int[] nums;
int size;
//end BIT
public void updateBITTree(int i, int delta) {
while(i<BITTree.length) {
BITTree[i]+=delta;
i+= i&(-i);
}
}
private int getSum(int i) {
int sum=0;
while(i>0) {
sum+=BITTree[i];
i-=(i&-i);
}
return sum;
}
}
/**
* Your NumArray object will be instantiated and called as such:
* NumArray obj = new NumArray(nums);
* obj.update(i,val);
* int param_2 = obj.sumRange(i,j);
*/
__________________________________________________________________________________________________
sample 43692 kb submission
class NumArray {
private int MAXN = 100100;
private int[] T = new int[MAXN];
private int[] nums;
private void add(int i, int val) {
for (i++; i < MAXN; i += (i & -i)) {
T[i] += val;
}
}
private int sum(int i) {
int s = 0;
for (i++; i > 0; i -= (i & -i)) {
s += T[i];
}
return s;
}
public NumArray(int[] nums) {
this.nums = nums;
for (int i = 0; i < nums.length; i++) {
add(i, nums[i]);
}
}
public void update(int i, int val) {
int delta = val - nums[i];
nums[i] = val;
add(i, delta);
}
public int sumRange(int i, int j) {
return sum(j) - sum(i-1);
}
}
/**
* Your NumArray object will be instantiated and called as such:
* NumArray obj = new NumArray(nums);
* obj.update(i,val);
* int param_2 = obj.sumRange(i,j);
*/
__________________________________________________________________________________________________