1. 对拍板子

以https://www.luogu.com.cn/problem/P7252 为例

正解

#include <iostream>
#include <cstring>
#include <cstdio>

using namespace std;

const int N = 5e4 + 10, M = N * 17;

int n, m, mn = N - 10;
int a[N], rt[N], idx;

struct node {
    int ls, rs;
    int val;
} t[M];

void update (int p) { t[p].val = t[t[p].ls].val + t[t[p].rs].val; }

int clone (int p) {
    t[ ++ idx] = t[p];
    return idx;
}

int modify (int p, int l, int r, int pos) {
    p = clone (p);
    if (l == r) {
        t[p].val ++;
        return p;
    }
    int mid = (l + r) >> 1;
    if (pos <= mid) t[p].ls = modify (t[p].ls, l, mid, pos);
    else t[p].rs = modify (t[p].rs, mid + 1, r, pos);
    update (p);
    return p;
}

void query (int p, int q, int l, int r, int len) {
    if (!p && !q) return;
    if (l == r) {
        cout << l << endl;
        return;
    }
    int mid = (l + r) >> 1;
    int lcnt = t[t[q].ls].val - t[t[p].ls].val, rcnt = t[t[q].rs].val - t[t[p].rs].val;

    if (lcnt > len) query (t[p].ls, t[q].ls, l, mid, len);
    else if (rcnt > len) query (t[p].rs, t[q].rs, mid + 1, r, len);
    else {
        cout << 0 << endl;
        return;
    }
}

int main () {

    freopen ("test/test.in", "r", stdin);
    freopen ("test/test.out", "w", stdout);

    cin >> n >> m;
    for (int i = 1; i <= n; i ++) {
        cin >> a[i];
        rt[i] = modify (rt[i - 1], 1, mn, a[i]);
    }
    for (int i = 1; i <= m; i ++) {
        int x, y;
        cin >> x >> y;
        query (rt[x - 1], rt[y], 1, mn, (y - x + 1) / 2);
    }

    return 0;
}

暴力

#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
#include <vector>
#include <queue>


using namespace std;

typedef long long ll;

const int N = 1e3 + 10, M = N << 1;

int n, m;
int a[N], b[N];
int cnt[N];

int main () {

	freopen ("test/test.in", "r", stdin);
	freopen ("test/ans.out", "w", stdout);

	cin >> n >> m;
	for (int i = 1; i <= n; i ++) {
		cin >> a[i];
	}

	for (int i = 1; i <= m; i ++) {
		int l, r, len;
		cin >> l >> r;
		len = (r - l + 1) / 2;
		for (int j = l; j <= r; j ++) {
			cnt[a[j]] ++;
		}
		bool ok = 0;
		for (int j = l; j <= r; j ++) {
			if (cnt[a[j]] > len) {
				cout << a[j] << endl;
				ok = 1;
				break;
			}
		}
		if (!ok) cout << 0 << endl;
		for (int j = l; j <= r; j ++) {
			cnt[a[j]] = 0;
		}
	}

	return 0;
}

随机数据

#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
#include <random>

using namespace std;

const int N = 1e5 + 10;

int n, m, sd;

mt19937 rng;

int rnd (int l, int r) {
	return rng () % (r - l + 1) + l;
}

int main () {
	freopen ("test/seed.txt", "r", stdin);
	scanf ("%d", &sd);
	rng.seed (sd);

	freopen ("test/test.in", "w", stdout);

	int n = rnd (1, 1e3), m = rnd (1, n);
	printf ("%d %d\n", n, m);
	for (int i = 1; i <= n; i ++) {
		printf ("%d ", rnd (1, n));
	}
	printf ("\n");

	for (int i = 1; i <= m; i ++) {
		int x = rnd (1, n), y = rnd (1, n);
		if (x > y) swap (x, y);
		printf ("%d %d\n", x, y);
	}

	fclose (stdout);
	freopen ("test/seed.txt", "w", stdout);
	printf ("%d", rnd (0, 2e9));

	return 0;
}

对拍文件

编译选项的话可以自己调
其中diff命令的选项说明一下

• -b：忽略空格数量变化，例如：a=1 和 a = 1 等价
• -B：忽略空行
• -Z：忽略行末空格

#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>

using namespace std;

int main () {
	system ("g++ -g -std=c++14 -o tt tt.cpp");
	system ("g++ -g -std=c++14 -o random random.cpp");
	system ("g++ -g -std=c++14 -o force force.cpp");
	int T;
	cin >> T;
	for (int i = 1; i <= T; i ++) {
		printf ("Case #%d ...", i);
		system ("./random");

		double fst = clock ();
		system ("./force");
		double fed = clock ();
		double st = clock ();
		system ("./tt");
		double ed = clock ();
		int sig = system ("diff -BZb test/ans.out test/test.out");
		if (sig != 0) {
			printf ("Wrong Answer!!!\n");
			return 0;
		}
		printf ("Accepted time: %.3lf  ftime: %.3lf\n", (ed - st) / 1000, (fed - fst) / 1000);
	}
	printf ("Congradulation!\n");

	return 0;
}

自动编译器

#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
#include <cmath>


using namespace std;


int main () {
	
	string name, compile, run, tmp;
	compile = "g++ -std=c++14 -Wall -fsanitize=address,undefined,leak -o ";
	cin >> name;
	tmp = ' ' + name + ".cpp";
	compile += name;
	compile += tmp;
	int sig = system (compile.c_str());
	if (sig != 0) {
		cout << "Compile Error\n";
		return 0;
	}
	run = "./" + name;
	system (run.c_str());


	return 0;
}