摘要：
Air RaidTime Limit:1000MSMemory Limit:10000KTotal Submissions:6275Accepted:3756DescriptionConsider a town where all the streets are one-way and each street leads from one intersection to another. It is also known that starting from an intersection and walking through town's streets you can never 阅读全文
摘要：
1 #include 2 #include 3 #define MAX_V 80 4 5 int V; //顶点数 6 int match[MAX_V]; //所匹配的顶点 7 bool used[MAX_V]; //DFS中用到 的访问标记 8 vector G[MAX_V]; //图的邻接表表示 9 10 //向图中增加一条边接u和v的边11 void add_edge(int u,int v)12 {13 G[u].push_back(v);14 G[v].push_ba... 阅读全文
摘要：
1 #include 2 #include 3 #include 4 #include 5 #define INF 0x7fffffff 6 #define MAX_V 210 7 8 using namespace std; 9 10 //用于表示边的结构体11 struct edge12 {13 int to; //终点14 int cap; //容量15 int rev; //反向边16 };17 18 int m,n;19 int iter[MAX_V]; //顶点到源咪的距离标号20 int level[MAX_V]; ... 阅读全文
摘要：
Dividing coinsIt's commonly known that the Dutch have invented copper-wire. Two Dutch men were fighting over a nickel, which was made of copper. They were both so eager to get it and the fighting was so fierce, they stretched the coin to great length and thus created copper-wire.Not commonly kno 阅读全文
摘要：
Optimal Array Multiplication SequenceGiven two arraysAandB, we can determine the arrayC=ABusing the standard definition of matrix multiplication:The number of columns in theAarray must be the same as the number of rows in theBarray. Notationally, let's say thatrows(A) andcolumns(A) are the numbe 阅读全文
摘要：
Let Me Count The WaysAfter making a purchase at a large department store, Mel's change was 17 cents. He received 1 dime, 1 nickel, and 2 pennies. Later that day, he was shopping at a convenience store. Again his change was 17 cents. This time he received 2 nickels and 7 pennies. He began to wond 阅读全文
摘要：
Goldbach's ConjectureIn 1742, Christian Goldbach, a German amateur mathematician, sent a letter to Leonhard Euler in which he made the following conjecture:Every number greater than 2 can be written as the sum of three prime numbers.Goldbach cwas considering 1 as a primer number, a convention th 阅读全文
摘要：
Error CorrectionA boolean matrix has theparity propertywhen each row and each column has an even sum, i.e. contains an even number of bits which are set. Here's a 4 x 4 matrix which has the parity property:1 0 1 00 0 0 01 1 1 10 1 0 1The sums of the rows are 2, 0, 4 and 2. The sums of the column 阅读全文