CodeForces 91B(單點查詢)
阿新 • • 發佈:2019-02-02
題意:有海象排隊,每個海象都有不滿意度,取決於離他前面的最遠的年齡比他小的海象和他直接站的海象數,給出佇列裡每個海象的年齡,輸出每個海象的不滿意度,如果沒有不滿意輸出-1。
題解:線段樹查詢最遠的比自己年齡小的海象的下標。
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;
const int N = 100050;
int n, a[N], tree[N << 2];
void pushup(int k) {
tree[k] = min(tree[k * 2 ], tree[k * 2 + 1]);
}
void build(int k, int left, int right) {
if (left == right) {
tree[k] = a[left];
return;
}
int mid = (left + right) / 2;
build(k * 2, left, mid);
build(k * 2 + 1, mid + 1, right);
pushup(k);
}
int query(int k, int left, int right, int l1, int r1, int x) {
if (left == right) {
if (tree[k] < x)
return left;
return -1;
}
int mid = (left + right) / 2;
if (r1 > mid && tree[k * 2 + 1] < x)
return query(k * 2 + 1, mid + 1, right, l1, r1, x);
else if (l1 <= mid)
return query(k * 2 , left, mid, l1, r1, x);
return -1;
}
int main() {
scanf("%d", &n);
for (int i = 1; i <= n; i++)
scanf("%d", &a[i]);
build(1, 1, n);
for (int i = 1; i < n; i++) {
int temp = query(1, 1, n, i + 1, n, a[i]);
if (temp == -1)
printf("-1 ");
else
printf("%d ", temp - i - 1);
}
printf("-1\n");
return 0;
}