0902饿了么笔试AK代码

Q1

package ali.eleme;

import java.util.Arrays;
import java.util.Scanner;

public class P1 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        int[] array = new int[n];
        for (int i = 0; i < n; i++) array[i] = scan.nextInt();
        Arrays.sort(array);
        int l = 0, r = n - 1;
        long ans = 0;
        while (r - l >= 2) {
            ans += array[l++] + array[r--];
            r--;
        }
        for (int i = l; i <= r; i++) ans += array[i];
        System.out.println(ans);
    }
}

Q2

package ali.eleme;

import java.util.Scanner;

public class P2 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int t = scan.nextInt();
        while (t-- > 0) {
            String s = scan.next(), tar = scan.next();
            int n = tar.length(), zeroTar = 0, zeroS = 0;
            for (int i = 0; i < n; i++) {
                if (tar.charAt(i) == '0') zeroTar++;
                if (s.charAt(i) == '0') zeroS++;
            }
            if (zeroS == n && zeroTar != n) System.out.println("NO");
            else if (zeroS != n && zeroTar == n) System.out.println("NO");
            else System.out.println("YES");
        }
    }
}

Q3

package ali.eleme;

import java.util.Scanner;

public class P3 {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt(), k = scan.nextInt();
        int[] array = new int[n];
        for (int i = 0; i < n; i++) array[i] = scan.nextInt();
        SegmentTree segmentTree = new SegmentTree(array);
        int ans = n, l = 0, r = 0;
        long sum = 0;
        while (r < n) {
            sum += array[r];
            while (sum >= k) {
                ans = Math.min(ans, r - l + 1);
                if (sum - segmentTree.query(1, 0, n - 1, l, r) >= k) {
                    ans = Math.min(ans, r - l);
                }
                sum -= array[l++];
            }
            r++;
        }
        System.out.println(ans);
    }

    static class SegmentTree {
        int[] tree, array;

        public SegmentTree(int[] array) {
            this.array = array;
            this.tree = new int[4 * array.length];
            build(1, 0, array.length - 1);
        }

        private void build(int node, int s, int e) {
            if (s == e) tree[node] = array[s];
            else {
                int mid = s + e >> 1;
                build(node << 1, s, mid);
                build(node << 1 | 1, mid + 1, e);
                tree[node] = Math.min(tree[node << 1], tree[node << 1 | 1]);
            }
        }

        public int query(int node, int s, int e, int l, int r) {
            if (s > r || e < l) return Integer.MAX_VALUE;
            if (s >= l && e <= r) return tree[node];
            int mid = s + e >> 1;
            int leftMin = query(node << 1, s, mid, l, r);
            int rightMin = query(node << 1 | 1, mid + 1, e, l, r);
            return Math.min(leftMin, rightMin);
        }
    }
}