CF280D k-Maximum Subsequence Sum(线段树)

在做这题时我一开始把\(tag\)写入了结构体

#include 
#include 
#include 
#include 
#include 
#include 
#define R(a,b,c) for(register int a = (b); a <= (c); ++a)
#define nR(a,b,c) for(register int a = (b); a >= (c); --a)
#define Fill(a,b) memset(a, b, sizeof(a))
#define Swap(a,b) ((a) ^= (b) ^= (a) ^= (b))
#define QWQ
#ifdef QWQ
#define D_e_Line printf("\n---------------\n")
#define D_e(x) cout << (#x) << " : " << x << "\n"
#define Pause() system("pause")
#define FileOpen() freopen("in.txt", "r", stdin)
#define FileSave() freopen("out.txt", "w", stdout)
#define TIME() fprintf(stderr, "\nTIME : %.3lfms\n", clock() * 1000.0 / CLOCKS_PER_SEC)
#else
#define D_e_Line ;
#define D_e(x) ;
#define Pause() ;
#define FileOpen() ;
#define FileSave() ;
#define TIME() ;
#endif
struct ios {
    template inline ios& operator >> (ATP &x) {
        x = 0; int f = 1; char c;
        for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-') f = -1;
        while(c >= '0' && c <='9') x = x * 10 + (c ^ '0'), c = getchar();
        x *= f;
        return *this;
    }
}io;
using namespace std;
template inline ATP Max(ATP a, ATP b) {
    return a > b ? a : b;
}
template inline ATP Min(ATP a, ATP b) {
    return a < b ? a : b;
}
template inline ATP Abs(ATP a) {
    return a < 0 ? -a : a;
}

const int N = 1e5 + 7;

int n;

struct RPG {
    int l, r, sum;
    bool operator < (const RPG &com) const {
        return sum < com.sum;
    }
    RPG operator + (const RPG &b) const {
        return (RPG){ l, b.r, sum + b.sum};
    }
};
struct nod {
    RPG lmax, lmin, rmin, rmax, mx, mn, all;
    bool tag;!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    bool operator < (const nod &com) const {
        return mx.sum < com.mx.sum;
    }
} t[N << 2];
#define ls rt << 1
#define rs rt << 1 | 1
#define lson rt << 1, l, mid
#define rson rt << 1 | 1, mid + 1, r
inline void Newnode(int rt, int pos, int val) {
    t[rt].lmax = t[rt].lmin = t[rt].rmax = t[rt].rmin = t[rt].mx = t[rt].mn = t[rt].all = (RPG){ pos, pos, val};
}
inline nod Merge(nod x, nod y) {
    nod s;
    s.lmax = max(x.lmax, x.all + y.lmax);
    s.lmin = min(x.lmin, x.all + y.lmin);
    s.rmax = max(y.rmax, x.rmax + y.all);
    s.rmin = min(y.rmin, x.rmin + y.all);
    s.mx = max(max(x.mx, y.mx), x.rmax + y.lmax);
    s.mn = min(min(x.mn, y.mn), x.rmin + y.lmin);
    s.all = x.all + y.all;
    return s;
}
inline void Pushup(int &rt) {
    t[rt] = Merge(t[ls], t[rs]);
}
inline void Pushrev(int rt) {
    swap(t[rt].lmax, t[rt].lmin);
    swap(t[rt].rmax, t[rt].rmin);
    swap(t[rt].mx, t[rt].mn);
    t[rt].lmax.sum = -t[rt].lmax.sum;
    t[rt].lmin.sum = -t[rt].lmin.sum;
    t[rt].rmax.sum = -t[rt].rmax.sum;
    t[rt].rmin.sum = -t[rt].rmin.sum;
    t[rt].mx.sum = -t[rt].mx.sum;
    t[rt].mn.sum = -t[rt].mn.sum;
    t[rt].all.sum = -t[rt].all.sum;
    t[rt].tag ^= 1;//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
}
inline void Pushdown(int rt) {
    if(!t[rt].tag) return;//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    Pushrev(ls);
    Pushrev(rs);
    t[rt].tag = 0;//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
}
inline void Modify(int rt, int l, int r, int x, int w) {
    if(l == r){
        Newnode(rt, x, w);
        return;
    }
    Pushdown(rt);
    int mid = (l + r) >> 1;
    if(x <= mid)
        Modify(lson, x, w);
    else
        Modify(rson, x, w);
    Pushup(rt);
}
inline void Updata(int rt, int l, int r, int L, int R) {
    if(L <= l && r <= R){
        Pushrev(rt);
        return;
    }
    Pushdown(rt);
    int mid = (l + r) >> 1;
    if(L <= mid) Updata(lson, L, R);
    if(R > mid) Updata(rson, L, R);
    Pushup(rt);
    return;
}
inline nod Query(int rt, int l, int r, int L, int R) {
    if(L <= l && r <= R) return t[rt];
    Pushdown(rt);
    int mid = (l + r) >> 1;
    if(R <= mid) return Query(lson, L, R);
    else if(L > mid) return Query(rson, L, R);
    else return Merge(Query(lson, L, R), Query(rson, L, R));
    Pushup(rt);
}

nod sta[N];
int top;
inline int Solve(int l, int r, int K) {
    int ans = 0;
    while(K--){
        nod s = Query(1, 1, n, l, r);
        if(s.mx.sum < 0) break;
        ans += s.mx.sum;
        Updata(1, 1, n, s.mx.l, s.mx.r);
        sta[++top] = s;
    }
    while(top){
        nod s = sta[top--];
        Updata(1, 1, n, s.mx.l, s.mx.r);
    }
    return ans;
}

int main() {
//FileOpen();
    io >> n;
    R(i,1,n){
        int x;
        io >> x;
        Modify(1, 1, n, i, x);
    }
    
    int m;
    io >> m;
    while(m--){
        int opt;
        io >> opt;
        if(opt){
            int l, r, K;
            io >> l >> r >> K;
            printf("%d\n", Solve(l, r, K));
        }
        else{
            int x, w;
            io >> x >> w;
            Modify(1, 1, n, x, w);
        }
    }
    
    return 0;
}

(注意打感叹号处)

一直没过样例,后来参考一位大佬的代码把\(tag\)单独放外面

#include 
#include 
#include 
#include 
#include 
#include 
#define R(a,b,c) for(register int a = (b); a <= (c); ++a)
#define nR(a,b,c) for(register int a = (b); a >= (c); --a)
#define Fill(a,b) memset(a, b, sizeof(a))
#define Swap(a,b) ((a) ^= (b) ^= (a) ^= (b))
#define QWQ
#ifdef QWQ
#define D_e_Line printf("\n---------------\n")
#define D_e(x) cout << (#x) << " : " << x << "\n"
#define Pause() system("pause")
#define FileOpen() freopen("in.txt", "r", stdin)
#define FileSave() freopen("out.txt", "w", stdout)
#define TIME() fprintf(stderr, "\nTIME : %.3lfms\n", clock() * 1000.0 / CLOCKS_PER_SEC)
#else
#define D_e_Line ;
#define D_e(x) ;
#define Pause() ;
#define FileOpen() ;
#define FileSave() ;
#define TIME() ;
#endif
struct ios {
    template inline ios& operator >> (ATP &x) {
        x = 0; int f = 1; char c;
        for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-') f = -1;
        while(c >= '0' && c <='9') x = x * 10 + (c ^ '0'), c = getchar();
        x *= f;
        return *this;
    }
}io;
using namespace std;
template inline ATP Max(ATP a, ATP b) {
    return a > b ? a : b;
}
template inline ATP Min(ATP a, ATP b) {
    return a < b ? a : b;
}
template inline ATP Abs(ATP a) {
    return a < 0 ? -a : a;
}

const int N = 1e5 + 7;

int n;

struct RPG {
    int l, r, sum;
    bool operator < (const RPG &com) const {
        return sum < com.sum;
    }
    RPG operator + (const RPG &b) const {
        return (RPG){ l, b.r, sum + b.sum};
    }
};
struct nod {
    RPG lmax, lmin, rmin, rmax, mx, mn, all;
    bool operator < (const nod &com) const {
        return mx.sum < com.mx.sum;
    }
} t[N << 2];
bool tag[N << 2]; //!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
#define ls rt << 1
#define rs rt << 1 | 1
#define lson rt << 1, l, mid
#define rson rt << 1 | 1, mid + 1, r
inline void Newnode(int rt, int pos, int val) {
    t[rt].lmax = t[rt].lmin = t[rt].rmax = t[rt].rmin = t[rt].mx = t[rt].mn = t[rt].all = (RPG){ pos, pos, val};
}
inline nod Merge(nod x, nod y) {
    nod s;
    s.lmax = max(x.lmax, x.all + y.lmax);
    s.lmin = min(x.lmin, x.all + y.lmin);
    s.rmax = max(y.rmax, x.rmax + y.all);
    s.rmin = min(y.rmin, x.rmin + y.all);
    s.mx = max(max(x.mx, y.mx), x.rmax + y.lmax);
    s.mn = min(min(x.mn, y.mn), x.rmin + y.lmin);
    s.all = x.all + y.all;
    return s;
}
inline void Pushup(int &rt) {
    t[rt] = Merge(t[ls], t[rs]);
}
inline void Pushrev(int rt) {
    swap(t[rt].lmax, t[rt].lmin);
    swap(t[rt].rmax, t[rt].rmin);
    swap(t[rt].mx, t[rt].mn);
    t[rt].lmax.sum = -t[rt].lmax.sum;
    t[rt].lmin.sum = -t[rt].lmin.sum;
    t[rt].rmax.sum = -t[rt].rmax.sum;
    t[rt].rmin.sum = -t[rt].rmin.sum;
    t[rt].mx.sum = -t[rt].mx.sum;
    t[rt].mn.sum = -t[rt].mn.sum;
    t[rt].all.sum = -t[rt].all.sum;
    tag[rt] ^= 1;//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
}
inline void Pushdown(int rt) {
    if(!tag[rt]) return;//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    Pushrev(ls);
    Pushrev(rs);
    tag[rt] = 0;//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
}
inline void Modify(int rt, int l, int r, int x, int w) {
    if(l == r){
        Newnode(rt, x, w);
        return;
    }
    Pushdown(rt);
    int mid = (l + r) >> 1;
    if(x <= mid)
        Modify(lson, x, w);
    else
        Modify(rson, x, w);
    Pushup(rt);
}
inline void Updata(int rt, int l, int r, int L, int R) {
    if(L <= l && r <= R){
        Pushrev(rt);
        return;
    }
    Pushdown(rt);
    int mid = (l + r) >> 1;
    if(L <= mid) Updata(lson, L, R);
    if(R > mid) Updata(rson, L, R);
    Pushup(rt);
    return;
}
inline nod Query(int rt, int l, int r, int L, int R) {
    if(L <= l && r <= R) return t[rt];
    Pushdown(rt);
    int mid = (l + r) >> 1;
    if(R <= mid) return Query(lson, L, R);
    else if(L > mid) return Query(rson, L, R);
    else return Merge(Query(lson, L, R), Query(rson, L, R));
    Pushup(rt);
}

nod sta[N];
int top;
inline int Solve(int l, int r, int K) {
    int ans = 0;
    while(K--){
        nod s = Query(1, 1, n, l, r);
        if(s.mx.sum < 0) break;
        ans += s.mx.sum;
        Updata(1, 1, n, s.mx.l, s.mx.r);
        sta[++top] = s;
    }
    while(top){
        nod s = sta[top--];
        Updata(1, 1, n, s.mx.l, s.mx.r);
    }
    return ans;
}

int main() {
//FileOpen();
    io >> n;
    R(i,1,n){
        int x;
        io >> x;
        Modify(1, 1, n, i, x);
    }
    
    int m;
    io >> m;
    while(m--){
        int opt;
        io >> opt;
        if(opt){
            int l, r, K;
            io >> l >> r >> K;
            printf("%d\n", Solve(l, r, K));
        }
        else{
            int x, w;
            io >> x >> w;
            Modify(1, 1, n, x, w);
        }
    }
    
    return 0;
}

(注意感叹号处)

就成功过掉了

这是为什么呢?是哪儿影响的呢?

大佬发话
原来是\(Merge()\)处没有初始化!

模拟费用流,线段树维护区间

#include 
#include 
#include 
#include 
#include 
#include 
#define R(a,b,c) for(register int a = (b); a <= (c); ++a)
#define nR(a,b,c) for(register int a = (b); a >= (c); --a)
#define Fill(a,b) memset(a, b, sizeof(a))
#define Swap(a,b) ((a) ^= (b) ^= (a) ^= (b))
#define QWQ
#ifdef QWQ
#define D_e_Line printf("\n---------------\n")
#define D_e(x) cout << (#x) << " : " << x << "\n"
#define Pause() system("pause")
#define FileOpen() freopen("in.txt", "r", stdin)
#define FileSave() freopen("out.txt", "w", stdout)
#define TIME() fprintf(stderr, "\nTIME : %.3lfms\n", clock() * 1000.0 / CLOCKS_PER_SEC)
#else
#define D_e_Line ;
#define D_e(x) ;
#define Pause() ;
#define FileOpen() ;
#define FileSave() ;
#define TIME() ;
#endif
struct ios {
    template inline ios& operator >> (ATP &x) {
        x = 0; int f = 1; char c;
        for(c = getchar(); c < '0' || c > '9'; c = getchar()) if(c == '-') f = -1;
        while(c >= '0' && c <='9') x = x * 10 + (c ^ '0'), c = getchar();
        x *= f;
        return *this;
    }
}io;
using namespace std;
template inline ATP Max(ATP a, ATP b) {
    return a > b ? a : b;
}
template inline ATP Min(ATP a, ATP b) {
    return a < b ? a : b;
}
template inline ATP Abs(ATP a) {
    return a < 0 ? -a : a;
}

const int N = 1e5 + 7;

int n;

struct RPG {
    int l, r, sum;
    bool operator < (const RPG &com) const {
        return sum < com.sum;
    }
    RPG operator + (const RPG &b) const {
        return (RPG){ l, b.r, sum + b.sum};
    }
};
struct nod {
    RPG lmax, lmin, rmin, rmax, mx, mn, all;
    bool tag;//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    bool operator < (const nod &com) const {
        return mx.sum < com.mx.sum;
    }
} t[N << 2];
#define ls rt << 1
#define rs rt << 1 | 1
#define lson rt << 1, l, mid
#define rson rt << 1 | 1, mid + 1, r
inline void ChangeNode(int rt, int pos, int val) {
    t[rt].lmax = t[rt].lmin = t[rt].rmax = t[rt].rmin = t[rt].mx = t[rt].mn = t[rt].all = (RPG){ pos, pos, val};
}
inline nod Merge(nod x, nod y) {
    nod s;
    s.lmax = max(x.lmax, x.all + y.lmax);
    s.lmin = min(x.lmin, x.all + y.lmin);
    s.rmax = max(y.rmax, x.rmax + y.all);
    s.rmin = min(y.rmin, x.rmin + y.all);
    s.mx = max(max(x.mx, y.mx), x.rmax + y.lmax);
    s.mn = min(min(x.mn, y.mn), x.rmin + y.lmin);
    s.all = x.all + y.all;
    s.tag = false;
    return s;
}
inline void Pushup(int &rt) {
    t[rt] = Merge(t[ls], t[rs]);
}
inline void Pushrev(int rt) {
    swap(t[rt].lmax, t[rt].lmin);
    swap(t[rt].rmax, t[rt].rmin);
    swap(t[rt].mx, t[rt].mn);
    t[rt].lmax.sum = -t[rt].lmax.sum;
    t[rt].lmin.sum = -t[rt].lmin.sum;
    t[rt].rmax.sum = -t[rt].rmax.sum;
    t[rt].rmin.sum = -t[rt].rmin.sum;
    t[rt].mx.sum = -t[rt].mx.sum;
    t[rt].mn.sum = -t[rt].mn.sum;
    t[rt].all.sum = -t[rt].all.sum;
    t[rt].tag ^= 1;//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
}
inline void Pushdown(int rt) {
    if(!t[rt].tag) return;//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
    Pushrev(ls);
    Pushrev(rs);
    t[rt].tag = 0;//!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
}
inline void Modify(int rt, int l, int r, int x, int w) {
    if(l == r){
        ChangeNode(rt, x, w);
        return;
    }
    Pushdown(rt);
    int mid = (l + r) >> 1;
    if(x <= mid)
        Modify(lson, x, w);
    else
        Modify(rson, x, w);
    Pushup(rt);
}
inline void Updata(int rt, int l, int r, int L, int R) {
    if(L <= l && r <= R){
        Pushrev(rt);
        return;
    }
    Pushdown(rt);
    int mid = (l + r) >> 1;
    if(L <= mid) Updata(lson, L, R);
    if(R > mid) Updata(rson, L, R);
    Pushup(rt);
    return;
}
inline nod Query(int rt, int l, int r, int L, int R) {
    if(L <= l && r <= R) return t[rt];
    Pushdown(rt);
    int mid = (l + r) >> 1;
    if(R <= mid) return Query(lson, L, R);
    else if(L > mid) return Query(rson, L, R);
    else return Merge(Query(lson, L, R), Query(rson, L, R));
    Pushup(rt);
}

nod sta[N];
int top;
inline int Solve(int l, int r, int K) {
    int ans = 0;
    while(K--){
        nod s = Query(1, 1, n, l, r);
        if(s.mx.sum < 0) break;
        ans += s.mx.sum;
        Updata(1, 1, n, s.mx.l, s.mx.r);
        sta[++top] = s;
    }
    while(top){
        nod s = sta[top--];
        Updata(1, 1, n, s.mx.l, s.mx.r);
    }
    return ans;
}

int main() {
//FileOpen();
    io >> n;
    R(i,1,n){
        int x;
        io >> x;
        Modify(1, 1, n, i, x);
    }
    
    int m;
    io >> m;
    while(m--){
        int opt;
        io >> opt;
        if(opt){
            int l, r, K;
            io >> l >> r >> K;
            printf("%d\n", Solve(l, r, K));
        }
        else{
            int x, w;
            io >> x >> w;
            Modify(1, 1, n, x, w);
        }
    }
    
    return 0;
}

CF280D k-Maximum Subsequence Sum(线段树)_第1张图片

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