蓝桥杯（3.6）

1221. 四平方和

import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner sc = new Scanner(System.in);int n = sc.nextInt();for(int i=0;i*i <= n;i++) {for(int j=i;i*i + j*j <= n;j++) {for(int k=j;i*i + j*j + k*k <= n;k++) {int t1 = n-i*i-j*j-k*k;int t2 = (int)Math.sqrt(t1);if(t1 >= k*k && t2*t2 == t1) {//加上t1 >= k*kSystem.out.println(i+" "+j+" "+k+" "+t2);return ;}}}}}}

import java.util.ArrayList;import java.util.Comparator;import java.util.List;import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner sc = new Scanner(System.in);int n = sc.nextInt();List<int[]> list = new ArrayList<>();//1for(int c = 0;c*c<=n;c++) {for(int d=c;c*c+d*d<=n;d++) {list.add(new int[] {c*c+d*d,c,d});}}//2list.sort(new Comparator<int[]>() {public int compare(int[] o1, int[] o2) {if(o1[0]!=o2[0])return o1[0]-o2[0];if(o1[1]!=o2[1])return o1[1]-o2[1];return o1[2]-o2[2];};});//3for(int a=0;a*a<=n;a++) {for(int b=a;a*a+b*b<=n;b++) {int t = n-a*a-b*b;//二分int l = 0,r = list.size()-1;while(l<r) {int mid = (l+r)/2;if(list.get(mid)[0] >= t)r = mid;elsel = mid+1;}//l或者rif(list.get(l)[0] == t) {int c = list.get(l)[1];int d = list.get(l)[2];System.out.println(a+" "+b+" "+c+" "+d);return ;}}}}}

import java.util.HashMap;import java.util.Map;import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner sc = new Scanner(System.in);int n = sc.nextInt();Map<Integer,int[]> map = new HashMap<>();//1for(int c = 0;c*c<=n;c++) {for(int d=c;c*c+d*d<=n;d++) {Integer cd = c*c + d*d;if(map.get(cd) == null)map.put(cd,new int[] {c,d});}}//2for(int a=0;a*a<=n;a++) {for(int b=a;a*a+b*b<=n;b++) {Integer t = n-a*a-b*b;if(map.get(t) != null) {int c = map.get(t)[0];int d = map.get(t)[1];System.out.println(a+" "+b+" "+c+" "+d);return ;}}}}}

795. 前缀和

import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner sc = new Scanner(System.in);int n = sc.nextInt();int m = sc.nextInt();int[] res = new int[n+1];int[] a = new int[n+1];for(int i=1;i<=n;i++)res[i] = sc.nextInt();//求前缀和数组for(int i=1;i<=n;i++) {a[i] = a[i-1] + res[i];}while(m-- != 0) {int l = sc.nextInt();int r = sc.nextInt();System.out.println(a[r]-a[l-1]);}}}

796. 子矩阵的和

import java.util.Scanner;public class Main {public static void main(String[] args) {Scanner sc = new Scanner(System.in);int n = sc.nextInt();int m = sc.nextInt();int q = sc.nextInt();int[][] a = new int[n+1][m+1];int[][] b = new int[n+1][m+1];for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)a[i][j] = sc.nextInt();for(int i=1;i<=n;i++)for(int j=1;j<=m;j++)b[i][j] = b[i][j-1]+b[i-1][j]-b[i-1][j-1]+a[i][j];//初始化前缀和数组while(q-- != 0) {int x1 = sc.nextInt();int y1 = sc.nextInt();int x2 = sc.nextInt();int y2 = sc.nextInt();System.out.println(b[x2][y2]-b[x2][y1-1]-b[x1-1][y2]+b[x1-1][y1-1]);}}}