塔子哥拿到了一个大小为的数组,她希望删除一个区间后,使得剩余所有元素的乘积未尾至少有k个0。塔子哥想知道,一共有多少种不同的删除方案?
第一行输入两个正整数 n,k
第二行输入n个正整数 a_i,代表塔子哥拿到的数组
1<=n , k<= 10e5
1<= a_i<=10e9
一个整数,代表删除的方案数
数论+双指针
package meituan.chun2025_1;
import java.util.Scanner;
public class Main4 {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int n = in.nextInt();
int k = in.nextInt();
int[] nums = new int[n];
long time_2 = 0,time_5 = 0;
int now;
for(int i=0;i<n;i++){
nums[i] = in.nextInt();
now = nums[i];
while(now>=5&&now%5==0){
now/=5;
time_5++;
}
while(now>=2&&now%2==0){
now/=2;
time_2++;
}
}
int left = 0;
long result = 0;
long now_time_2 = 0,now_time_5 =0;
for(int i=0;i<n;i++){
now = nums[i];
while(now>=5&&now%5==0){
now/=5;
now_time_5++;
}
while(now>=2&&now%2==0){
now/=2;
now_time_2++;
}
long zero_now = Math.min(time_5-now_time_5,time_2-now_time_2);
while(left<=i&&left<n&&zero_now<k){
now = nums[left++];
while(now>=5&&now%5==0){
now/=5;
now_time_5--;
}
while(now>=2&&now%2==0){
now/=2;
now_time_2--;
}
zero_now = Math.min(time_5-now_time_5,time_2-now_time_2);
}
result+=i-left+1;
}
System.out.println(result);
}
}
package meituan.chun2025_1;
import java.util.*;
class UnionFind {
private int[] parent;
private int[] size;
private int count;
public UnionFind(int n) {
this.parent = new int[n];
this.size = new int[n];
this.count = n;
for (int i = 0; i < n; i++) {
parent[i] = i;
size[i] = 1;
}
}
public int find(int p) {
while (p != parent[p]) {
parent[p] = parent[parent[p]];
p = parent[p];
}
return p;
}
public void union(int p, int q) {
int rootP = find(p);
int rootQ = find(q);
if (rootP == rootQ) {
return;
}
if (size[rootP] > size[rootQ]) {
parent[rootQ] = rootP;
size[rootP] += size[rootQ];
} else {
parent[rootP] = rootQ;
size[rootQ] += size[rootP];
}
count--;
}
public int getCount() {
return count;
}
}
class Function{
public void Add(HashMap<Integer,HashSet<Integer>> is_exist,int x, int y){
int source = Math.max(x,y);
int target = Math.min(x,y);
HashSet<Integer> now_set = is_exist.getOrDefault(source,new HashSet<Integer>());
now_set.add(target);
is_exist.put(source,now_set);
}
public boolean isExist(HashMap<Integer,HashSet<Integer>> is_exist,int x, int y){
int source = Math.max(x,y);
int target = Math.min(x,y);
HashSet<Integer> now_set = is_exist.getOrDefault(source,new HashSet<Integer>());
if (now_set.isEmpty())
return false;
if (!now_set.contains(target))
return false;
return true;
}
public void Remove(HashMap<Integer,HashSet<Integer>> is_exist,int x, int y){
int source = Math.max(x,y);
int target = Math.min(x,y);
HashSet<Integer> now_set = is_exist.get(source);
now_set.remove(target);
}
}
public class Main5 {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
int n = in.nextInt();
int m = in.nextInt();
int q = in.nextInt();
int[][] relation = new int[m][2];
UnionFind solution = new UnionFind(n+1);
Function function = new Function();
HashMap<Integer,HashSet<Integer>> is_exist = new HashMap<>();
HashMap<Integer,HashSet<Integer>> is_forget = new HashMap<>();
//input relation
for(int i=0;i<m;i++){
int x = in.nextInt();
int y = in.nextInt();
relation[i][0] = x;
relation[i][1] = y;
function.Add(is_exist,x,y);
}
//input op
int[][] op = new int[n][3];
for(int i=0;i<q;i++){
op[i][0] = in.nextInt();
op[i][1] = in.nextInt();
op[i][2] = in.nextInt();
if(op[i][0]==1)
function.Add(is_forget,op[i][1],op[i][2]);
}
// add union
for(int i=0;i<m;i++){
if (!function.isExist(is_forget,relation[i][0],relation[i][1]))
solution.union(relation[i][0],relation[i][1]);
}
Deque<Boolean> result = new LinkedList<>();
for(int i=q-1;i>=0;i--){
int[] now = op[i];
if (now[0]==1){
if (!function.isExist(is_exist,now[1],now[2]))
continue;
function.Remove(is_exist,now[1],now[2]);
solution.union(now[1],now[2]);
}
else
{
result.offerFirst(solution.find(now[1])==solution.find(now[2]));
}
}
while(!result.isEmpty())
{
boolean now = result.pollFirst();
if (now)
System.out.println("Yes");
else
System.out.println("No");
}
}
}