每天记背

附：NOI 大纲

快读模板#

inline int read() {
	long long x = 0, w = 1;
	char ch = getchar ();
	for (; ch < '0' || ch > '9'; ch = getchar()) if (ch == '-') w = -1;
	for (; ch >= '0' && ch <= '9'; ch = getchar()) x = x * 10 + ch - '0';
	return x * w;
} 

链式前向星#

struct Edge {
	int to;
	int next;
}e[maxn];

int tot;
int head[maxn];

void Add (int u, int v) {
	e[++ tot].to = v;
	e[tot].next = head[u];
	head[u] = tot;
}

快速幂#

inline int qpow (int a, int b) {
    int ans = 1, base = a;
    while (b > 0) {
        if (b & 1) ans *= base;
        base *= base;
        b >>= 1;
    }
    return ans;
}

dijkstra#

int n, m, s, d[N];
struct edge {
    int v, w;
};
vector <edge> g[N];
priority_queue< pair<int, int> > q;

void dijkstra(int s) {
    for (int i = 1; i <= n; i ++) d[i] = inf;
    d[s] = 0;
    q.push({0, s});
    while (!q.empty()) {
        auto t = q.top();
        q.pop();
        int u = t.second;
        for (auto ed : g[u]) {
            int v = ed.v, w = ed.w;
            if (d[v] > d[u] + w) {
                d[v] = d[u] + w;
                q.push({-d[v], v});
            }
        }
    }
}

Floyed#

for (int k = 1; k <= n; k ++)
    for (int i = 1; i <= n; i ++)
        for (int j = 1; j <= n; j ++)
            f[i][j] = min(f[i][j], f[i][k] + f[k][j]);

线性筛#

int prime[maxn];
bool isPrime[maxn];

void xxs (ll n) {
	int cnt = 0;
	memset (isPrime, 1, sizeof(isPrime));
	isPrime[1] = 0;
	for (int i = 2; i <= n; i++) {
		if (isPrime[i]) 
			prime[++cnt] = i;
		for (int j = 1; j <= cnt && i * prime[j] <= n; j++) {
			isPrime[i * prime[j]] = 0;
			if (i % prime[j] == 0)
				break;
		}
	}
}

并查集#

int fa[maxn];

inline int get(int x) {
	if (fa[x] == x) return x;
    return fa[x] = find(fa[x]);
}

inline void join(int f1, int f2) {
    f1 = find(f1), f2 = find(f2);
    if (f1 != f2) fa[f1] = f2;
}

施工中......