HDU 5353 Average 贪心

  1 #pragma comment(linker, "/STACK:102400000,102400000")
  2 #include <iostream>
  3 #include <cstdio>
  4 #include <fstream>
  5 #include <algorithm>
  6 #include <cmath>
  7 #include <deque>
  8 #include <vector>
  9 #include <queue>
 10 #include <string>
 11 #include <cstring>
 12 #include <map>
 13 #include <stack>
 14 #include <set>
 15 #define LL long long
 16 #define INF 0x3f3f3f3f
 17 #define MAXN 200005
 18 using namespace std;
 19 struct Node
 20 {
 21     int x, y;
 22     Node(int x = 0, int y = 0):x(x), y(y){};
 23 };
 24 vector<Node> res;
 25 int n;
 26 LL sum;
 27 LL a[MAXN];
 28 int f[MAXN];
 29 int main()
 30 {
 31 #ifndef ONLINE_JUDGE
 32     freopen("in.txt", "r", stdin);
 33     //freopen("out.txt", "w", stdout);
 34 #endif // OPEN_FILE
 35    int T;
 36    scanf("%d", &T);
 37    for(int cas = 1; cas <= T; cas++){
 38         scanf("%d", &n);
 39         sum = 0;
 40         for(int i = 1; i <= n; i++){
 41             scanf("%d", &a[i]);
 42             a[i + n] = a[i];
 43             sum += a[i];
 44         }
 45         if(sum % n != 0){
 46             printf("NO\n");
 47             continue;
 48         }
 49         LL ave = sum / n;
 50         memset(f, 0, sizeof(f));
 51         bool noans = false;
 52         for(int i = 1; i < 2 * n; i++){
 53             if(a[i] == ave){
 54                 continue;
 55             }
 56             if(a[i] < ave){
 57                 if(ave - a[i] > 2){
 58                     noans = true;
 59                     break;
 60                 }
 61                 a[i]++;
 62                 a[i + 1]--;
 63                 f[i] = 1;
 64                 continue;
 65             }
 66             if(a[i] > ave){
 67                 if(a[i] - ave > 2){
 68                     noans = true;
 69                     break;
 70                 }
 71                 a[i]--;
 72                 a[i + 1]++;
 73                 f[i] = -1;
 74             }
 75         }
 76         if(noans){
 77             printf("NO\n");
 78             continue;
 79         }
 80         noans = true;
 81         int cnt = 1;
 82         int pos = 0;
 83         for(int i = 2; i <= 2 * n; i++){
 84             if(a[i] == a[i - 1]){
 85                 cnt++;
 86             }
 87             else{
 88                 cnt = 1;
 89             }
 90             if(cnt == n){
 91                 noans = false;
 92                 pos = i;
 93                 break;
 94             }
 95         }
 96         if(noans){
 97             printf("NO\n");
 98             continue;
 99         }
100         printf("YES\n");
101         int x, y;
102         res.clear();
103         for(int i = pos - n + 1; i <= pos; i++){
104             if(f[i] == 0){
105                 continue;
106             }
107             if(f[i] == 1){
108                 x = i + 1;
109                 y = i;
110             }
111             else{
112                 x = i;
113                 y = i + 1;
114             }
115             if(x > n){
116                 x -= n;
117             }
118             if(y > n){
119                 y -= n;
120             }
121             res.push_back(Node(x, y));
122         }
123         printf("%d\n", res.size());
124         for(int i = 0; i < res.size(); i++){
125             printf("%d %d\n", res[i].x, res[i].y);
126         }
127    }
128 }