Add missing #include.

Change-Id: If32d858c9d9eec9f53753007e0831e56f25d32d4

internal/ceres/compressed_col_sparse_matrix_utils.h

diff --git a/internal/ceres/compressed_col_sparse_matrix_utils.h b/internal/ceres/compressed_col_sparse_matrix_utils.h
index fceb764..f88a5bd 100644
--- a/internal/ceres/compressed_col_sparse_matrix_utils.h
+++ b/internal/ceres/compressed_col_sparse_matrix_utils.h
@@ -31,6 +31,7 @@
 #ifndef CERES_INTERNAL_COMPRESSED_COL_SPARSE_MATRIX_UTILS_H_
 #define CERES_INTERNAL_COMPRESSED_COL_SPARSE_MATRIX_UTILS_H_
 
+#include <algorithm>
 #include <vector>
 
 #include "ceres/internal/disable_warnings.h"