You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
68 lines
1.8 KiB
Java
68 lines
1.8 KiB
Java
public class SegmentTreeIntervalAddMax {
|
|
|
|
int n;
|
|
int[] tmax;
|
|
int[] tadd; // tadd[i] affects tmax[i], tadd[2*i+1] and tadd[2*i+2]
|
|
|
|
void push(int root) {
|
|
tmax[root] += tadd[root];
|
|
tadd[2 * root + 1] += tadd[root];
|
|
tadd[2 * root + 2] += tadd[root];
|
|
tadd[root] = 0;
|
|
}
|
|
|
|
public SegmentTreeIntervalAddMax(int n) {
|
|
this.n = n;
|
|
tmax = new int[4 * n];
|
|
tadd = new int[4 * n];
|
|
}
|
|
|
|
public int max(int from, int to) {
|
|
return max(from, to, 0, 0, n - 1);
|
|
}
|
|
|
|
int max(int from, int to, int root, int left, int right) {
|
|
if (from == left && to == right) {
|
|
return tmax[root] + tadd[root];
|
|
}
|
|
push(root);
|
|
int mid = (left + right) >> 1;
|
|
int res = Integer.MIN_VALUE;
|
|
if (from <= mid)
|
|
res = Math.max(res, max(from, Math.min(to, mid), 2 * root + 1, left, mid));
|
|
else if (to > mid)
|
|
res = Math.max(res, max(Math.max(from, mid + 1), to, 2 * root + 2, mid + 1, right));
|
|
return res;
|
|
}
|
|
|
|
public void add(int from, int to, int delta) {
|
|
add(from, to, delta, 0, 0, n - 1);
|
|
}
|
|
|
|
void add(int from, int to, int delta, int root, int left, int right) {
|
|
if (from == left && to == right) {
|
|
tadd[root] += delta;
|
|
return;
|
|
}
|
|
// push can be skipped for add, but is necessary for other operations such as set
|
|
push(root);
|
|
int mid = (left + right) >> 1;
|
|
if (from <= mid)
|
|
add(from, Math.min(to, mid), delta, 2 * root + 1, left, mid);
|
|
if (to > mid)
|
|
add(Math.max(from, mid + 1), to, delta, 2 * root + 2, mid + 1, right);
|
|
tmax[root] = Math.max(tmax[2 * root + 1] + tadd[2 * root + 1], tmax[2 * root + 2] + tadd[2 * root + 2]);
|
|
}
|
|
|
|
// tests
|
|
public static void main(String[] args) {
|
|
SegmentTreeIntervalAddMax t = new SegmentTreeIntervalAddMax(10);
|
|
t.add(0, 9, 1);
|
|
t.add(2, 4, 2);
|
|
t.add(3, 5, 3);
|
|
System.out.println(t.max(0, 9));
|
|
System.out.println(t.tmax[0] + t.tadd[0]);
|
|
System.out.println(t.max(0, 0));
|
|
}
|
|
}
|