线段树模板

线段树区间更新：

//0 x y v: [x,y]内元素都加上v//1 x y: [x,y]内元素的和typedef long long ll;const int N = 100010;struct node{    int l, r;    ll val, mark;}tr[N*4];int cas = 0;void push_up(int k){    tr[k].val = tr[k<<1].val + tr[k<<1|1].val;}void push_down(int k){    if(tr[k].mark)    {        tr[k<<1].mark += tr[k].mark, tr[k<<1|1].mark += tr[k].mark;        tr[k<<1].val += (tr[k<<1].r - tr[k<<1].l + 1) * tr[k].mark;        tr[k<<1|1].val += (tr[k<<1|1].r - tr[k<<1|1].l + 1) * tr[k].mark;        tr[k].mark = 0;    }}void build(int l, int r, int k){    tr[k].l = l, tr[k].r = r, tr[k].mark = 0;    if(l == r)    {        tr[k].val = 0; return;    }    int mid = (l + r) >> 1;    build(l, mid, k << 1);    build(mid + 1, r, k << 1|1);    push_up(k);}void update(int l, int r, int val, int k){    if(l <= tr[k].l && tr[k].r <= r)    {        tr[k].mark += val;        tr[k].val += 1LL * (tr[k].r - tr[k].l + 1) * val;        return;    }    push_down(k);    int mid = (tr[k].l + tr[k].r) >> 1;    if(l <= mid) update(l, r, val, k << 1);    if(r > mid) update(l, r, val, k << 1|1);    push_up(k);}ll query(int l, int r, int k){    if(l <= tr[k].l && tr[k].r <= r) return tr[k].val;    push_down(k);    int mid = (tr[k].l + tr[k].r) >> 1;    ll res = 0;    if(l <= mid) res += query(l, r, k << 1);    if(r > mid) res += query(l, r, k << 1|1);    return res;}int main(){    int t, n, m, a, b, c, d;    scanf("%d", &t);    while(t--)    {        scanf("%d%d", &n, &m);        build(1, n, 1);        printf("Case %d:\n", ++cas);        for(int i = 0; i < m; i++)        {            scanf("%d", &a);            if(a == 0)            {//下标从0开始，故+1                scanf("%d%d%d", &b, &c, &d);                update(b+1, c+1, d, 1);            }            else            {                scanf("%d%d", &b, &c);                printf("%lld\n", query(b+1, c+1, 1));            }        }    }    return 0;}

线段树区间合并：

#include <bits/stdc++.h>using namespace std;//给定一个长度为n的01串，接下来一个m，有m个操作，操作有两种：0 a b查询区间内最长连续1的长度，1 a b反转区间内，0变1，1变0const int N = 100010;struct node{    int l, r;    int lone, lzero, rone, rzero, max1, max0;//分别维护左起1，左起0，右起1，右起0，区间中1的最大长度，0的最大长度    int len, mark; //区间长度，lazy标记}tr[N*4];int val[N];void push_up(int k){    tr[k].lone = tr[k<<1].lone;    if(tr[k<<1].lone == tr[k<<1].len) tr[k].lone += tr[k<<1|1].lone;//左子树左起1的长度等于区间长度，那么直接加上右子树的左起1长度    tr[k].lzero = tr[k<<1].lzero;    if(tr[k<<1].lzero == tr[k<<1].len) tr[k].lzero += tr[k<<1|1].lzero;    tr[k].rone = tr[k<<1|1].rone;    if(tr[k<<1|1].rone == tr[k<<1|1].len) tr[k].rone += tr[k<<1].rone;    tr[k].rzero = tr[k<<1|1].rzero;    if(tr[k<<1|1].rzero == tr[k<<1|1].len) tr[k].rzero += tr[k<<1].rzero;    tr[k].max1 = max(tr[k<<1].rone + tr[k<<1|1].lone, max(tr[k<<1].max1, tr[k<<1|1].max1));    tr[k].max0 = max(tr[k<<1].rzero + tr[k<<1|1].lzero, max(tr[k<<1].max0, tr[k<<1|1].max0));}void push_down(int k){    if(tr[k].mark)//0与1互变，所以所有的维护信息也要互换    {        tr[k<<1].mark ^= tr[k].mark;        tr[k<<1|1].mark ^= tr[k].mark;        swap(tr[k<<1].lone, tr[k<<1].lzero);        swap(tr[k<<1].rone, tr[k<<1].rzero);        swap(tr[k<<1].max1, tr[k<<1].max0);        swap(tr[k<<1|1].lone, tr[k<<1|1].lzero);        swap(tr[k<<1|1].rone, tr[k<<1|1].rzero);        swap(tr[k<<1|1].max1, tr[k<<1|1].max0);        tr[k].mark = 0;    }}void build(int l, int r, int k){    tr[k].l = l, tr[k].r = r, tr[k].mark = 0, tr[k].len = r - l + 1;    if(l == r)    {        if(val[l]) tr[k].lone = tr[k].rone = tr[k].max1 = 1, tr[k].lzero = tr[k].rzero = tr[k].max0 = 0;        else tr[k].lzero = tr[k].rzero = tr[k].max0 = 1, tr[k].lone = tr[k].rone = tr[k].max1 = 0;        return;    }    int mid = (tr[k].l + tr[k].r) >> 1;    build(l, mid, k << 1);    build(mid + 1, r, k << 1 | 1);    push_up(k);}void update(int l, int r, int k){    if(l <= tr[k].l && tr[k].r <= r)    {        tr[k].mark ^= 1;        swap(tr[k].rone, tr[k].rzero);        swap(tr[k].lone, tr[k].lzero);        swap(tr[k].max1, tr[k].max0);        return;    }    push_down(k);    int mid = (tr[k].l + tr[k].r) >> 1;    if(l <= mid) update(l, r, k << 1);    if(r > mid) update(l, r, k << 1 | 1);    push_up(k);}int query(int l, int r, int k){    if(l == tr[k].l && tr[k].r == r)        return tr[k].max1;    push_down(k);    int mid = (tr[k].l + tr[k].r) >> 1;    if(r <= mid) return query(l, r, k << 1); //查询区间位于左子树    else if(l > mid) return query(l, r, k << 1 | 1); //查询区间位于右子树    else //查询区间被分割    {        int left = 0, right = 0, midd = 0;        midd = min(mid - l + 1, tr[k<<1].rone) + min(r - mid, tr[k<<1|1].lone);        left = query(l, mid, k << 1);        right = query(mid + 1, r, k << 1 | 1);        return max(midd, max(left, right));    }}int main(){    int n, m, a, b, c;    while(~ scanf("%d", &n))    {        for(int i = 1; i <= n; i++)            scanf("%d", val + i);        build(1, n, 1);        scanf("%d", &m);        for(int i = 0; i < m; i++)        {            scanf("%d%d%d", &a, &b, &c);            if(a) update(b, c, 1);            else printf("%d\n", query(b, c, 1));        }    }    return 0;}