Sliding Window

Sun, 22 Mar 2026 18:00:00 +0800

滑动窗口的最大值

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public class Main{
 public static void main(String[] args){
 Scanner sc=new Scanner(System.in);
 int n=sc.nextInt();
 int[] ans=new int[n];
 for(i=0;i<n;i++){
 ans[i]=sc.nextInt();
 }
 int m=sc.nextInt();
 int left=0,right=0;
 int res=Integer.MIN_VALUE;
 int tmp=0;

 while(right<n){
 if(right-left+1<m){
 tmp+=ans[left];
 right++;
 continue;
 }
 if(right-left+1>m){
 tmp-=ans[left];
 left++;
 }
 tmp+=ans[right];
 res=Math.max(res,tmp);
 right++;
 }
 System.out.println(res);
 }
}

最左侧冗余覆盖子串

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public class Main{
 public static void main(String[] args){
 Scanner sc=new Scanner(System.in);
 String pattern=sc.nextLine();
 String text=sc.nextLint();

 int maxExtraChars=sc.nextInt();
 sc.close();

 int startIndex=-1;
 int[] patternFreq=new int[26];
 for(char c:pattern.toCharArray()){
 patternFreq[c-'a']++;
 }
 int left=0,right=0;
 int remainingMatches=pattern.length();
 int[] windowFreq=new int[26];
 while(right<text.length()){
 char rightChar=text.charAt(right);
 windowFreq[right-'a']++;
 if(windowFreq[rightChar-'a']<=patternFreq[rightChar-'a']){
 remainingMatches--;
 }
 if(right-left+1>pattern.length()+maxExtraChars){
 char leftChar=text.charAt(left);
 if(windowFreq[leftChar-'a']<=patternFreq[leftChar-'a']){
 remainingMatches++;
 }
 windowFreq[leftChar-'a']--;
 left++;
 }
 if(remainingMatches==0){
 startIndex=left;
 break;
 }
 right++;
 }
 System.out.println(startIndex);
 }
}

恢复数字序列

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public class Main{
 static void addNumberToMap(int num,Map<Character,Integer> count){
 for(char c:String.valueOf(num).toCharArray()){
 count.put(c,count.getOrDefault(c,0)+1);
 }
 }
 static void removeNumberFromMap(int num,Map<Character,Integer> count){
 for(char c:String.valueOf(num).toCharArray()){
 count.put(c,count.get(c)-1);
 if(count.get(c)==0){
 count.remove(c);
 }
 }
 }
 public static void main(String[] args){
 Scanner scanner=new Scanner(System.in);
 String s=scanner.next();
 int k=scanner.nextInt();
 scanner.close();
 Mao<Character,Integer> base=new HashMap<>();
 for(char c:s.toCharArray()){
 base.put(c,base.getOrDeault(c,0)+1);
 }
 Map<Character,Integer> count=new HashMap<>();
 for(int i=1;i<=k;i++){
 addNumberToMap(i,count);
 }
 if(count.equals(base)){
 System.out.println(1);
 return;
 }
 for(int i=2;i<=1000-k+1;i++){
 removeNumberFromMap(i-1,count);
 addNumberToMap(i+k-1,count);
 if(count.equals(base)){
 System.out.println(i);
 return;
 }
 }
 }
}

敌情监控

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public class Main{
 public static void main(String[] args){
 Scanner scanner=new Scanner(System.in);
 int n=scanner.nextInt();
 int k=scanner.nextInt();
 int l=scanner.nextInt();
 int[] nums=new int[n];
 for(int i=0;i<n;i++){
 nums[i]=scanner.nextInt();
 }
 for(int i=0;i<l;i++){
 String command=sc.next();
 int arg1=scanner.nextInt();
 int arg2=scanner.nextInt();
 if(command.equals("Add")){
 int index=arg1-1;
 nums[index]+=arg2;
 }else if(command.equals("Sub")){
 int index=arg1-1;
 nums[index]-=arg2;
 }else{
 int start=arg1-1;
 int end=arg2-1;
 int currentSum=0;
 for(int j=start;j<start+k;j++){
 currentSum+=nums[j];
 }
 int minSum=currentSum;
 for(int idx=start+i;idx<=end-k+1;idx++){
 currentSum=currentSum-nums[idx-1]+nums[idx+k-1];
 minSum=Math.min(minSum,currentSum);
 }
 System.out.println(minSum);
 }
 }
 scanner.close();
 }
}

Sliding Window on Sunjianlin's Blog

Sliding Window

滑动窗口的最大值

最左侧冗余覆盖子串

恢复数字序列

敌情监控