模板库（数据结构）

堆（heap）

#include<cstdio>#include<cstring>#include<algorithm>using namespace std;const int N = 1e6 + 10; struct Heap {    int a[N], size;    void clear() {        memset(a, 0, sizeof(a));        size = 0;    }    void push(int x) {        a[++size] = x;        for(int son = size, fa = son>>1; fa; son = fa, fa = son>>1) {            if(a[son] < a[fa]) swap(a[son], a[fa]);            else break;        }    }    int top() {        return a[1];    }    void pop() {        a[1] = a[size--];        for(int fa = 1, son = fa<<1; son <= size; fa = son, son = fa<<1) {            if(son < size && a[son] > a[son+1]) son++;            if(a[son] < a[fa]) swap(a[son], a[fa]);            else break;        }    }}heap;int main() {    int n, op, x;    scanf("%d", &n);    heap.clear();    for(int i = 1; i <= n; ++i) {        scanf("%d", &op);        if(op == 1) {            scanf("%d", &x);            heap.push(x);        } else if(op == 2) {            printf("%d\n", heap.top());        } else if(op == 3) {            heap.pop();        }    }    return 0;}

并查集

#include<cstdio>#include<cstdlib>#include<ctime>using namespace std;const int N = 1e4 + 10;int n, m, op, x, y, f[N];int find(int x) {    int r = x;    while(r != f[r]) r = f[r];    int i = x, j;    while(f[i] != r) {        j = f[i];        f[i] = r;        i = j;    }    return r;}void merge(int x, int y) {    if(rand()%2) f[x] = y;    else f[y] = x;}int main() {    srand(time(NULL));    scanf("%d%d", &n, &m);    for(int i = 1; i <= n; ++i) f[i] = i;    for(int i = 1; i <= m; ++i) {        scanf("%d%d%d", &op, &x, &y);        int fx = find(x), fy = find(y);        if(op == 1) {            if(fx != fy) merge(fx, fy);        } else if(op == 2) {            if(fx == fy) printf("Y\n");            else printf("N\n");        }    }    return 0;}

st表（RMQ问题）

#include<cstdio>#include<algorithm>#include<cmath>using namespace std;const int N = 1e5 + 10;int n, m, a[N], l, r, d[N][32];void pre() {    for(int i = 1; i <= 30; ++i)        for(int j = 1; j+(1<<(i-1)) <= n; ++j)            d[j][i] = max(d[j][i-1], d[j+(1<<(i-1))][i-1]);}int RMQ(int l, int r) {    int k = log(r-l+1)/log(2);    return max(d[l][k], d[r-(1<<k)+1][k]);}int main() {    scanf("%d%d", &n, &m);    for(int i = 1; i <= n; ++i) scanf("%d", &d[i][0]);    pre();    for(int i = 1; i <= m; ++i) {        scanf("%d%d", &l, &r);        printf("%d\n", RMQ(l, r));    }    return 0;}

差分数组（多次修改，一次查询）(借教室

#include<cstdio>#include<cstring>const int N = 1e6 + 10;long long sup[N], d[N];int needs[N], s[N], t[N];int n, m;bool judge(int x) {    memset(needs, 0, sizeof(needs));    for(int i = 1; i <= x; ++i) {        needs[s[i]] += d[i];        needs[t[i]+1] -= d[i];    }    for(int i = 1; i <= n; ++i) {        needs[i] += needs[i-1];        if(needs[i] > sup[i]) {            return false;        }    }    return true;}int main() {    scanf("%d%d", &n, &m);    for(int i = 1; i <= n; ++i) {        scanf("%d", &sup[i]);    }    for(int i = 1; i <= m; ++i) {        scanf("%d%d%d", &d[i], &s[i], &t[i]);    }    int l = 0, r = m, mid, ans = m;    while(l <= r) {        mid = (l+r)>>1;        if(judge(mid)) {            ans = mid;            l = mid+1;        } else r = mid-1;    }    if(ans != m) printf("-1\n%d\n", ans+1);    else printf("0\n");    return 0;}

线段树（区间修改，区间查询）

#include<cstdio>#define lson l,mid,rt<<1#define rson mid+1,r,rt<<1|1typedef long long ll;const int N = 1e5 + 10;int n, m, op, l, r;ll sum[N<<2], col[N<<2], a[N], val;void update(int rt) {    sum[rt] = sum[rt<<1] + sum[rt<<1|1];}void build(int l, int r, int rt) {    col[rt] = 0;    if(l == r) {        sum[rt] = a[l];        return;    }    int mid = (l+r)>>1;    build(lson); build(rson);    update(rt);}void color(int l, int r, int rt, int val) {    col[rt] += val;    sum[rt] += val*(r-l+1);}void push_col(int l, int r, int rt) {    if(col[rt]) {        int mid = (l+r)>>1;        color(lson, col[rt]);        color(rson, col[rt]);        col[rt] = 0;    }}void modify(int l, int r, int rt, int nowl, int nowr, ll val) {    if(nowl <= l && r <= nowr) {        color(l, r, rt, val);        return;    }    push_col(l, r, rt);    int mid = (l+r)>>1;    if(nowl <= mid) modify(lson, nowl, nowr, val);    if(mid < nowr) modify(rson, nowl, nowr, val);    update(rt);}ll query(int l, int r, int rt, int nowl, int nowr) {    if(nowl <= l && r <= nowr) {        return sum[rt];    }    push_col(l, r, rt);    int mid = (l+r)>>1;    ll ans = 0;    if(nowl <= mid) ans += query(lson, nowl, nowr);    if(mid < nowr) ans += query(rson, nowl, nowr);    return ans;}int main() {    scanf("%d%d", &n, &m);    for(int i = 1; i <= n; ++i) {        scanf("%lld", &a[i]);    }    build(1, n, 1);    for(int i = 1; i <= m; ++i) {        scanf("%d%d%d", &op, &l, &r);        if(op == 1) {            scanf("%lld", &val);            modify(1, n, 1, l, r, val);        } else if(op == 2) {            printf("%lld\n", query(1, n, 1, l, r));        }    }    return 0;}

树状数组（单点修改，区间查询）

#include<cstdio>#define lowbit(x) ((x)&(-(x)))const int N = 500000 + 10;int z[N], n, m, x, y, op;void modify(int pos, int val) {    for(; pos <= n; pos += lowbit(pos)) z[pos] += val;}int query(int l, int r) {    int ans = 0; l--;    for(; r; r -= lowbit(r)) ans += z[r];    for(; l; l -= lowbit(l)) ans -= z[l];    return ans;}int main() {    scanf("%d%d", &n, &m);    for(int i = 1; i <= n; ++i) {        scanf("%d", &x);        modify(i, x);    }    for(int i = 1; i <= m; ++i) {        scanf("%d%d%d", &op, &x, &y);        if(op == 1) {            modify(x, y);        } else if(op == 2) {            printf("%d\n", query(x, y));        }    }    return 0;}