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Codeforces Round #271 (Div. 2)

2024-07-25 22:36:56   217人阅读

Codeforces Round #271 (Div. 2)

题目链接

A：水题，分LR考虑一下即可，脸滚键盘可以滚出字符串

B：就是预处理一下，然后每次询问输出即可

C：暴力旋转，判断正方形即可

D：递推dp[i] = dp[i - 1] + dp[i - k]

E：先把高度hash，每次多一个高度，就利用二分去找满足对应的hash值，找出这些最大值，这步用线段树维护，然后记录每个位置答案用来输出

F：每个区间最小值才会满足，并且如果最小值不等于整个区间gcd答案就为0了，如果等于就可以找出这个区间对应这个最小值有几个，用数组记录二分即可

代码：

#include <cstdio>
#include <cstring>
#include <iostream>
#include <string>
using namespace std;

string str[3];
string A, sb;
int mv;

char get(char sb) {
	for (int i = 0; i < 3; i++) {
		for (int j = 0; j < str[i].length(); j++) {
			if (str[i][j] == sb) return str[i][j + mv];
		}
	}
}

int main() {
	str[0] = "qwertyuiop";
	str[1] = "asdfghjkl;";
	str[2] = "zxcvbnm,./";
	cin >> A >> sb;
	if (A[0] == 'L') mv = 1;
	else mv = -1;
	for (int i = 0; i < sb.length(); i++) {
		cout << get(sb[i]);
	}
	cout << endl;
	return 0;
}

B：

#include <cstdio>
#include <cstring>

const int N = 1000005;
int n, a, vis[N];

int main() {
	scanf("%d", &n);
	int s = 0;
	for (int i = 1; i <= n; i++) {
		scanf("%d", &a);
		for (int j = 0; j < a; j++) {
			s++;
			vis[s] = i;
		}
	}
	int m;
	scanf("%d", &m);
	while (m--) {
		scanf("%d", &a);
		printf("%d\n", vis[a]);
	}
	return 0;
}

C：

#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;

const int INF = 0x3f3f3f3f;
int n;
double x[4], y[4], a[4], b[4];
double sx[4], sy[4];
int ans;

void rote(double &x, double &y, double a, double b) {
	x -= a; y -= b;
	double x1 = -y;
	double y1 = x;
	x = x1 + a;
	y = y1 + b;
}

double save[10];
int sn;

double dis(double x1, double y1, double x2, double y2) {
	double dx = x1 - x2;
	double dy = y1 - y2;
	return sqrt(dx * dx + dy * dy);
}

bool eq(double a, double b) {
	return fabs(a - b) < 1e-9;
}

bool judge() {
	sn = 0;
	for (int i = 0; i < 4; i++) {
		for (int j = i + 1; j < 4; j++) {
			save[sn++] = dis(sx[i], sy[i], sx[j], sy[j]);
		}
	}
	sort(save, save + sn);
	if (fabs(save[0]) < 1e-9) return false;
	for (int i = 0; i < 3; i++)
		if (!eq(save[i], save[i + 1])) return false;
	if (!eq(save[4], save[5])) return false;
	if (!eq(save[3] * sqrt(2.0), save[4])) return false;
	return true;
}

void dfs(int u, int sum) {
	if (sum >= ans) return;
	if (u == 4) {
		if (judge())
			ans = min(ans, sum);
		return;
	}
	double xx = x[u], yy = y[u];
	for (int i = 0; i <= 3; i++) {
		sx[u] = xx; sy[u] = yy;
		dfs(u + 1, sum + i);
		rote(xx, yy, a[u], b[u]);
	}
}

int solve() {
	ans = INF;
	dfs(0, 0);
	if (ans == INF) ans = -1;
	return ans;
}

int main() {
	scanf("%d", &n);
	while (n--) {
		for (int i = 0; i < 4; i++)
			scanf("%lf%lf%lf%lf", &x[i], &y[i], &a[i], &b[i]);
		printf("%d\n", solve());
	}
	return 0;
}

D:

#include <cstdio>
#include <cstring>

const int MOD = 1e9 + 7;

typedef long long ll;
const int N = 100005;

int t, k, a, b;
int dp[N];

int main() {
	dp[0] = 1;
	scanf("%d%d", &t, &k);
	for (int i = 1; i < N; i++) {
		dp[i] = dp[i - 1];
		if (i >= k) dp[i] = (dp[i] + dp[i - k]) % MOD;
	}
	for (int i = 1; i < N; i++)
		dp[i] = (dp[i] + dp[i - 1]) % MOD;
	int m;
	while (t--) {
		scanf("%d%d", &a, &b);
		printf("%d\n", ((dp[b] - dp[a - 1]) % MOD + MOD) % MOD);
	}
	return 0;
}

E:

#include <cstdio>
#include <cstring>
#include <map>
#include <algorithm>
using namespace std;
typedef long long ll;

const int INF = 0x3f3f3f3f;
const int N = 100005;
int n, hn;
ll d, h[N], hh[N];
int dp[N];
map<ll, int> hash;
map<ll, int>::iterator it;

#define lson(x) ((x<<1)+1)
#define rson(x) ((x<<1)+2)

struct Node {
	int l, r, Max;
} node[N * 4];

ll abss(ll x) {
	if (x < 0) return -x;
	return x;
}

void build(int l, int r, int x = 0) {
	node[x].l = l; node[x].r = r; node[x].Max = 0;
	if (l == r) {
		return;
	}
	int mid = (l + r) / 2;
	build(l, mid, lson(x));
	build(mid + 1, r, rson(x));
}

void pushup(int x) {
	node[x].Max = max(node[lson(x)].Max, node[rson(x)].Max);
}

void add(int v, int val, int x = 0) {
	if (node[x].l == node[x].r) {
		node[x].Max = max(node[x].Max, val);
		return;
	}
	int mid = (node[x].l + node[x].r) / 2;
	if (v <= mid) add(v, val, lson(x));
	if (v > mid) add(v, val, rson(x));
	pushup(x);
}

int query(int l, int r, int x = 0) {
	if (node[x].l >= l && node[x].r <= r)
		return node[x].Max;
	int ans = -INF;
	int mid = (node[x].l + node[x].r) / 2;
	if (l <= mid) ans = max(ans, query(l, r, lson(x)));
	if (r > mid) ans = max(ans, query(l, r, rson(x)));
	return ans;
}

int out[N], on = 0;
int main() {
	scanf("%d%lld", &n, &d);
	for (int i = 1; i <= n; i++) {
		scanf("%lld", &h[i]);
		hh[i] = h[i];
	}
	sort(h + 1, h + n + 1);
	for (int i = 1; i <= n; i++) {
		if (hash.count(h[i])) continue;
		hash[h[i]] = hn++;
	}
	build(0, hn - 1);
	for (int i = 1; i <= n; i++) {
		dp[i] = 1;
		it = hash.upper_bound(hh[i] - d);
		if (it != hash.begin()) {
			it--;
			int l = it->second;
			int tmp = query(0, l);
			if (tmp)
				dp[i] = max(dp[i], tmp + 1);
		}
		it = hash.lower_bound(hh[i] + d);
		if (it != hash.end()) {
			int r = it->second;
			int tmp = query(r, hn - 1);
			if (tmp)
				dp[i] = max(dp[i], tmp + 1);
		}
		add(hash[hh[i]], dp[i]);
	}
	int ans = 0, ans_v;
	for (int i = 1; i <= n; i++) {
		if (ans < dp[i]) ans = dp[i], ans_v = i;
	}
	printf("%d\n", dp[ans_v]);
	int tot = dp[ans_v];
	ll pre = hh[ans_v];
	out[0] = ans_v;
	on = 1;
	tot--;
	for (int i = ans_v; i >= 1; i--) {
		if (dp[i] == tot && abss(hh[i] - pre) >= d) {
			out[on++] = i;
			pre = hh[i];
			tot--;
		}
	}
	for (int i = on - 1; i >= 0; i--) printf("%d%c", out[i], i == 0 ? '\n' : ' ');
	return 0;
}

F:

#include <cstdio>
#include <cstring>
#include <map>
#include <vector>
#include <algorithm>
using namespace std;

const int N = 100005;

int n, s[N];
map<int, vector<int> > g;

#define lson(x) ((x<<1)+1)
#define rson(x) ((x<<1)+2)

struct Node {
	int l, r, gcd, Min;
} node[N * 4];

int gcd(int a, int b) {
	return b == 0 ? a : gcd(b, a % b);
}

void pushup(int x) {
	node[x].gcd = gcd(node[lson(x)].gcd, node[rson(x)].gcd);
	node[x].Min = min(node[lson(x)].Min, node[rson(x)].Min);
}

void build(int l, int r, int x = 0) {
	node[x].l = l; node[x].r = r;
	if (l == r) {
		node[x].Min = node[x].gcd = s[l];
		return;
	}
	int mid = (l + r) / 2;
	build(l, mid, lson(x));
	build(mid + 1, r, rson(x));
	pushup(x);
}

const int INF = 0x3f3f3f3f;
int gc, an, cnt[N];

void query(int l, int r, int x = 0) {
	if (node[x].l >= l && node[x].r <= r) {
		if (an > node[x].Min) {
			an = node[x].Min;
		}
		gc = gcd(gc, node[x].gcd);
		return;
	}
	int mid = (node[x].l + node[x].r) / 2;
	if (l <= mid) query(l, r, lson(x));
	if (r > mid) query(l, r, rson(x));
}

int main() {
	scanf("%d", &n);
	for (int i = 1; i <= n; i++) {
		scanf("%d", &s[i]);
		if (g[s[i]].size() == 0) cnt[i] = 0;
		else cnt[i] = cnt[g[s[i]][g[s[i]].size() - 1]] + 1;
		g[s[i]].push_back(i);
	}
	build(1, n);
	int m;
	scanf("%d", &m);
	int l, r;
	while (m--) {
		scanf("%d%d", &l, &r);
		an = INF;
		gc = 0;
		query(l, r);
		if (an != gc) printf("%d\n", r - l + 1);
		else {
			int left = *lower_bound(g[an].begin(), g[an].end(), l);
			int right = *--upper_bound(g[an].begin(), g[an].end(), r);
			left = cnt[left];
			right = cnt[right];
			printf("%d\n", r - l - right + left);
		}
	}
	return 0;
}


Codeforces Round #271 (Div. 2)


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