LOJ#3095. 「SNOI2019」字符串

如果两个串\(i,j\)比较\(i < j\)，如果离\(a_{i}\)最近的不同的数是\(a_{k}\)，如果\(j < k\)那么\(i\)排在\(j\)前面

否则的话如果\(a_{k} < a_{i}\)，那么\(i\)排在\(j\)前

于是写个比较函数扔到sort里就可以了

#include <bits/stdc++.h>
#define fi first
#define se second
#define pii pair<int,int>
#define mp make_pair
#define pb push_back
#define space putchar(' ')
#define enter putchar('\n')
#define eps 1e-10
#define MAXN 1000005
#define ba 47
//#define ivorysi
using namespace std;
typedef long long int64;
typedef unsigned int u32;
typedef double db;
template<class T>
void read(T &res) {
    res = 0;T f = 1;char c = getchar();
    while(c < '0' || c > '9') {
    if(c == '-') f = -1;
    c = getchar();
    }
    while(c >= '0' && c <= '9') {
    res = res * 10 +c - '0';
    c = getchar();
    }
    res *= f;
}
template<class T>
void out(T x) {
    if(x < 0) {x = -x;putchar('-');}
    if(x >= 10) {
    out(x / 10);
    }
    putchar('0' + x % 10);
}
int N,id[MAXN],nxt[MAXN];
char s[MAXN];
bool cmp(int a,int b) {
    bool f = 0;
    if(a > b) {f = 1;swap(a,b);}
    if(b < nxt[a]) f ^= 1;
    else {
    f ^= (s[nxt[a]] < s[a]);
    }
    return f;
}
void Solve() {
    read(N);
    scanf("%s",s + 1);
    for(int i = 1 ; i <= N ; ++i) {
    id[i] = i;
    }
    nxt[N] = N + 1;
    for(int i = N - 1 ; i >= 1 ; --i) {
    if(s[i + 1] != s[i]) nxt[i] = i + 1;
    else nxt[i] = nxt[i + 1];
    }
    sort(id + 1,id + N + 1,cmp);
    for(int i = 1 ; i <= N ; ++i) {
    out(id[i]);space;
    }
    enter;
}
int main() {
#ifdef ivorysi
    freopen("f1.in","r",stdin);
#endif
    Solve();
}