1999 LSU Computer Science High School Programming Contest
Novice Problem 6
Orange Barrels

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Problem Statement

When highways are being worked on, the repair crews use Orange Barrels to tell you when you can/should move over (lanes are closed or they re-open). The Larry-Darrel-Darrel Construction Company always puts 13 Orange Barrels before a lane ends (13 per each lane). They always put 9 Orange Barrels when you regain a lane. You are to read in a series of lane widths and determine how many barrels you see while traveling that stretch of road and how many times the number of lanes changes.

Sample Input Data:

3 
2 
4 
3
0
4 
5 
2 
3 
4 
5 
6 
3 
4 
5
0
-1

NOTE: Each highway will end when you encounter a zero (0). You will stop processing when you encounter a negative one (-1).

Sample Output:

This highway changed width 3 times and we saw 44 Orange Barrels.
This highway changed width 9 times and we saw 141 Orange Barrels.

NOTE: Do not worry about the formatting of numeric output (leading/trailing spaces around numbers are acceptable).

Explanation of Calculation:

The highway 3 2 4 3 would be calculated as follows:

    The highway starts at 3 lanes wide and you have seen no barrels
  1. The highway narrows by 1 lane to 2 lanes wide and you see 13 barrels for a total of 13 barrels
  2. The highway widens by 2 lanes to 4 lanes wide and you see 18 barrels for a total of 31 barrels
  3. The highway narrows by 1 lane to 3 lanes wide and you see 13 barrels for a total of 44 barrels



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Clarifications:






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Source Code for a Solution to this Problem

// preprocessor directives
#include <stdio.h>


int main(void)
{
   int lanes;     /* width of current highway */
   int past;      /* previous width of highway */
   int count;     /* number of times that highway width changes */
   int barrels;   /* number of barrels that have been seen */

   scanf("%d",&lanes);  /* priming read */

   while(lanes != -1)   /* while more highways to process */
   {
     barrels = 0; count = 0;  /* initialize variables for this highway */
     past = lanes;         /* set past so count won't get incremented */
     
     while (lanes != 0)  /* while more lanes in this highway */
     {
       if (lanes != past)   /* have we have a change in number of lanes */
        {
          if (lanes > past)
           barrels += 9 * (lanes - past);   /* highway got wider */
          else
           barrels += 13 * (past - lanes);  /* highway got narrower */

           count++;                         /* highway width changed */

           past = lanes;                    /* remember current width */
        }
       scanf("%d",&lanes);                  /* get new lane-width */
     } /* END of while more lanes in this highway */ 

    printf("This highway changed width %d times and we saw %d Orange Barrels.\n", count, barrels);
 
    scanf("%d",&lanes);   /* new highway ? */

   } 

   return 0;

}//main

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Sample Input

3 
2 
4 
3 
0
4 
5 
2 
3 
4 
5 
6 
3 
4 
5 
0
-1

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Sample Output

This highway changed width 3 times and we saw 44 Orange Barrels.
This highway changed width 9 times and we saw 141 Orange Barrels.

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Judge Data Set 1 - Input

3 
2 
4 
3 
0
4 
5 
2 
3 
4 
5 
6 
3 
4 
5 
0
4 
2 
3 
4 
2 
3 
4
5 
2 
0
8
6
4
5
4
2
5
0
3
3
5
6
7
2
1
4
0
-1
2 
3 
4 
2 
4 
3 
0

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Judge Data Set 1 - Output

This highway changed width 3 times and we saw 44 Orange Barrels.
This highway changed width 9 times and we saw 141 Orange Barrels.
This highway changed width 8 times and we saw 136 Orange Barrels.
This highway changed width 6 times and we saw 127 Orange Barrels.
This highway changed width 6 times and we saw 141 Orange Barrels.

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Judge Data Set 2 - Input

12
6
4
7
6
9
8
10
0
1
1
0
8
8
8
9
0
9
8
7
6
5
4
3
2
1
2
3
4
5
6
7
8
9
0
9
2
8
3
7
1
6
4
6
0
-1

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Judge Data Set 2 - Output

This highway changed width 7 times and we saw 202 Orange Barrels.
This highway changed width 0 times and we saw 0 Orange Barrels.
This highway changed width 1 times and we saw 9 Orange Barrels.
This highway changed width 16 times and we saw 176 Orange Barrels.
This highway changed width 8 times and we saw 413 Orange Barrels.

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© 1999 LSU High School Programming Contest

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