day4_17
BC149 简写单词
https://www.nowcoder.com/practice/0cfa856bf0d649b88f6260d878f35bb4?tpId=290&tqId=39937&ru=/exam/oj
j
思路：模拟
代码：
java"> public static void main(String[] args) {Scanner in = new Scanner(System.in);while(in.hasNext()){char c = in.next().charAt(0);if(c>='a'&&c<='z'){System.out.print((char)(c-32));}else{System.out.print(c);}}}
dd爱框框
https://ac.nowcoder.com/acm/contest/11211/F
思路：滑动窗口（同向双指针）
1.从1开始计数的
2.区间内的数字必须严格大于0，因为如果区间中存在小于0的数，left在滑动的时候，可能会增大，会倒逼right回退。只有严格大于0的数，随着left滑动，区间之和才会减小。right就会向后移动。
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进窗口：sum += arr[right]
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判断条件:sum >=x
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更新结果：right-left+1 < retlen retleft = left, retright = right
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出窗口：sum-= arr[left]
代码：
java">import java.util.*;
import java.io.*;
public class Main{public static void main(String[] args )throws IOException{Read in = new Read();int n = in.nextInt(),x = in.nextInt();int[]arr = new int[n+1];for(int i = 1; i<=n ; i++){arr[i] = in.nextInt();}int left = 1,right = 1,sum = 0;int retleft = -1,retright = -1,retlen = n;while(right<=n){//进窗口sum += arr[right];while(sum>=x){//更新结果if(right-left+1 < retlen){retleft = left;retright = right;retlen = right-left+1;}sum -= arr[left++];//出窗口}right++;}System.out.println(retleft+" "+retright); }
}
class Read{StringTokenizer st = new StringTokenizer("");BufferedReader bf = new BufferedReader(new InputStreamReader(System.in));String next()throws IOException{while(!st.hasMoreTokens()){st = new StringTokenizer(bf.readLine());}return st.nextToken();}String nextLine()throws IOException{return bf.readLine();}int nextInt()throws IOException{return Integer.parseInt(next());}long nextLong()throws IOException{return Long.parseLong(next());}double nextDouble()throws IOException{return Double.parseDouble(next());}
}
除2！
https://ac.nowcoder.com/acm/contest/8563/A
思路：模拟+贪心+堆
1.优先级队列确保出队的都是最大值
2.如果出队/2之后仍是偶数，再次进队。
代码：
java">import java.util.*;
import java.util.Scanner;
public class Main{public static void main(String[] args){Scanner in = new Scanner(System.in);int n = in.nextInt();int k = in.nextInt();PriorityQueue<Integer> heap = new PriorityQueue<>((a,b)->{return b-a;});long sum = 0,x;for(int i = 0; i<n; i++){x = in.nextLong();sum += x;if(x%2 == 0){heap.add((int)x);}}while(k-- != 0 && !heap.isEmpty()){long t = heap.poll() / 2;sum -= t;if(t%2 == 0){heap.add((int)t);}}System.out.println(sum);}
}
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